The Night of Al-Qadr occurs in the last ten nights of Ramadaan during an odd night (i.e. 21st, 23rd, 25th, 27th or 29th). However the scholars differ as to if it is fixed to one of these odd nights every year or if it changes every year to a different odd-numbered night. Below are the sayings of two of our great scholars, Muhammad Ibn Saalih Al-‘Uthaimeen and Muhammad Naasir-ud-Deen Al-Albaanee (may Allaah have mercy on both of them).
The Night of Al-Qadr has a Fixed Date:
The best night in Ramadaan is the Night of Al-Qadr, based on the Prophet’s saying:
“Whoever performs the night prayer on the Night of Al-Qadr with firm faith and while seeking reward, his past sins will be forgiven.” 
It is on the twenty-seventh night of Ramadaan according to the strongest opinion. A majority of the ahaadeeth comply with this, including the hadeeth of Zurr Ibn Hubaysh who said:
“I heard Ubay Bin Ka’ab (radyAllaahu ‘anhu) say when it was said to him that ‘Abdullaah Ibn Mas’ood (radyAllaahu ‘anhu) said “Whoever performs the night prayer (every night) throughout the year will achieve the Night of Al-Qadr.” He (Ubay Bin Ka’ab) said: “May Allaah have mercy on him, his intention was that the people not (grow lazy) and depend solely (on just one night). By the One of whom there is no deity worthy of worship beside Him, it is indeed in Ramadaan. And by Allaah I know on which night it is. It is on the night that Allaah’s Messenger (sallAllaahu ‘alayhi wa sallam) commanded us to perform the Night Prayer. It is on the twenty-seventh night. Its sign is that the sun rises on its following morning bright with no rays.”
In one report this is raised to being a saying of the Prophet (sallAllaahu ‘alayhi wa sallam). 
[Imaam Al-Albaanee in his book Qiyaam Ramadaan (pg. 18-19)]
The Night of Al-Qadr is to be sought:
The Night of Al-Qadr is in the last ten nights of Ramadaan, based on the saying of the Prophet:
“Search for the Night of Al-Qadr in the last ten nights of Ramadaan.” [Al-Bukhaaree and Muslim]
And it falls in one of the odd nights more likely than on the even nights, based on the Prophet’s (sallAllaahu ‘alayhi wa sallam) saying: “Search for the Night of Al-Qadr in the odd nights of the last ten nights of Ramadaan.” [Al-Bukhaaree]
And it is closer to the last seven nights, based on the hadeeth of Ibn ‘Umar (radyAllaahu ‘anhumaa) that: “Some men from the Companions of Allaah’s Messenger saw the Night of Al-Qadr in a dream during the last seven nights (of Ramadaan). So the Prophet (sallAllaahu ‘alayhi wa sallam) said: ‘I see that all of your dreams agree that it (the Night of Al-Qadr) is in the last seven nights. So whoever wants to search for it, then let him search for it in the last seven nights.'” [Al-Bukhaaree and Muslim]
And it is also based on the hadeeth in Muslim from Ibn ‘Umar that the Prophet said: “Look for it in the last ten nights. But if one of you becomes weak or is unable, then do not let the remaining (last) seven nights overcome him.”
Amongst the odd nights in the last seven nights, it is closest to the twenty-seventh night due to the hadeeth of Ubay Bin Ka’ab (radyAllaahu ‘anhu) who said: “By Allaah, I know which night it is. It is on the night that Allaah’s Messenger commanded us to perform the Night Prayer. It is on the twenty-seventh night.” [Muslim]
The Night of Al-Qadr is not specified to one fixed night throughout all the years. Rather, it constantly changes. So one year it could occur on the twenty-seventh night for example and on another year it could occur on the twenty-fifth night, according to Allaah’s Will and Wisdom.
What directs us to this is the Prophet’s (sallAllaahu ‘alayhi wa sallam) saying: “Look for it (i.e. the Night of Al-Qadr) when there remain nine nights, when there remains seven nights, or when there remains five nights (i.e. 21st, 23rd, and 25th respectively without mention of 27th).”
Al-Haafidh Ibn Hajr said in Fath-ul-Baaree: “The most strongest opinion is that it is on an odd night in the last ten nights and that it constantly changes.”
Allaah has hidden knowledge of its occurrence from His servants out of mercy for them so that they can increase their actions in the search for it during these honorable nights, by praying, making dhikr and supplicating. So they grow and increase in the nearness to Allaah and His reward. And He also kept it hidden from them as a test for them to distinguish who amongst them struggles and makes an effort to find it and who is lazy and negligent. This is since whoever constantly strives for something, he will exert himself in his search for it and trouble himself in finding it and achieving it.
And perhaps Allaah discloses the time of its occurrence to some of His servants through signs and signals, which one is able to see, just as the Prophet saw its sign that he would be prostrating in mud on its following morning. So it rained on that night and he prayed the (following) morning (Fajr) prayer in mud.
[Imaam Muhammad Ibn Saalih Al-‘Uthaimeen in his book Majaalis Shahr Ramadaan (pg. 106-107)]
 Reported by Al-Bukhaaree, Muslim and others from the narration of Abu Hurairah (raa) and by Ahmad (5/318) from the narration of ‘Ubaadah Ibn As-Saamit (raa). The addition to it in […] belongs to him and to Muslim from Abu Hurairah.
 Reported by Muslim and others and it is referenced in Saheeh Abee Dawood (1247)
Recommended act during Last Ten Days of Ramadhan
In the name of God, Most Gracious, Most Merciful We have indeed revealed this (Message) in the Night of Power: And what will explain to thee what the Night of Power is? The Night of Power is better than a thousand months. Therein come down the angels and the Spirit by God’s permission, on every errand: Peace!…This until the rise of morn!
Surah 97 The Holy Qur’an
The Holy Qur’an contains a short surah dedicated to Laylatul Qadr. Surah Al-Qadr is the 97th surah and consists of five verses. However, these short verses carry great meaning and guidance. They tell us all we need to know about the essence and spirit of Laylatul Qadr.
Laylatul Qadr falls sometime within the last 10 days of Ramadhan.
“Seek it in Ramadan in the last ten nights. For verily, it is during the odd nights, the twenty-first, or the twenty-third, or the twenty-fifth, or the twenty-seventh, or the twenty-ninth, or during the last night.” Sahih Hadith Ahmad 5:318
Laylatul Qadr is the most blessed night. A person who misses it has indeed missed a great amount of good. If an individual wants to obey his Lord, increase the good deeds in his record and have all past sins forgiven, they should take part in Laylatul Qadr.
“Whoever stays up (in prayer and remembrance of Allah) on the Night of Qadr fully believing (in Allah’s promise of reward for that night) and hoping to seek reward (from Allah alone and not from people), he shall be forgiven for his past sins.” Sahih Hadith Bukhari / Muslim
We should strive to find this night, and then pass it in worship and obedience. If this is done for the sake of Allah, with sincerity, then all past sins will be forgiven. However, if a person misses out on worship during Laylatul Qadr they truly are a deprived person.
This night is full of reward and blessing and is equivalent to a thousand nights of worship. Anyone who takes part in Laylatul Qadr will have worshipped an equivalent of eighty three years and three months. It is as if a person has spent an entire lifetime in non-stop worship.
“The Night of Power is better than a thousand months.” 97:3 The Holy Quran
“Allah’s Messenger, sallallahu `alayhi wa sallam, looked back at the previous communities and saw that his community lived for a much shorter period in comparison to them. He was concerned about how his community would be able to gain as many rewards as those of the previous communities. So when Allah the Exalted saw the concerns in the heart of His Beloved, sallallahu `alayhi wa sallam, then he, sallallahu `alayhi wa sallam, was given Laylatul-Qadr, which is more virtuous than a thousand months.” (Imâm Mâlik, Muatta)
Worship during this night can take on many forms. Here are a few suggestions to help you through Laylatul Qadr:
• Plan ahead if you are working. If you are going to spend a night awake in worship, book the following day off.
• Take regular breaks during the night to avoid getting over-exhausted. Try switching between different forms of worship instead.
• Perform Itikaaf (seclusion in a mosque for worship) – If possible, take a vacation for the last 10 days of Ramadhan. If you cannot stay at your local mosque ask family or friends to help out during your Itikaaf at home. If you cannot spend all 10 days in Itikaaf, then do as many days as you can – even if it is only one day.
• Increase the recitation of the Qur’an, and reflect on the meaning of the verses, especially the verses used in Salah. This will help you concentrate.
• Increase Salah (prayer).
• Find out if there are any events organised, and take your family along.
Doing all of the above activities may be too much to do throughout the night but is far better than social gatherings and meaningless talk that we stay awake for.
If your Arabic is not very strong then there are many good English translations of Qur’an and Hadith, which can be used instead. Other useful reading might include books of tafsir (Qura’n commentary), books on the lives of the Prophets (upon whom be peace), and books of fiqh (Islamic jurisprudence) as well as Du’a books.
The days of Laylatul-Qadr are an important time for worship, especially the last 10 days. We should pray sincerely from our hearts in order to be saved from the hellfire. This is a good opportunity not only to pray for ourselves but also for our fellow brothers and sisters, for if we can not do anything else then our prayers will help.
Ibn Abbas (RA) heard the Prophet (SAAWS) advising someone, saying, “Take advantage of five before five: You’re youth before your old age, your health before your sickness, your wealth before your poverty, your free time before you become occupied, and your life before your death.”
May Allah help us to purify our hearts, strengthen our faith, and enable us to meet every challenge, and overcome every difficulty in our lives. May Allah allow us to serve Him with sincerity in our work, study, professional, business, family and social lives. When the time comes for us finally to return to Him, may Allah admit us to the companionship of those whom He loves. Ameen…