All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
There is no difference between the Witr and the daily obligatory prayers in the manner that they are performed in terms of reciting Takbeerat Al-Ihraam (Opening Takbeer), the recitation of the Faatihah and then a soorah, bowing, rising from bowing, prostrating, rising from the prostration, sitting between the two prostrations, reciting Tashahhud, and the Tasleem. All these acts of the prayer are the same for the Witr and the obligatory prayers. However, there is a difference between them in the number of Rak‘ahs (units of prayer). The Witr prayer may be performed as one, three, or five Rak‘ahs, based on the hadeeth wherein Abu Ayyoob Al-Ansaari, may Allah be pleased with him, said, “The Messenger of Allah, sallallahu ‘alayhi wa sallam, said, ‘The Witr is a duty on every Muslim, so whoever wishes to pray the Witr with five Rak‘ahs, let him do so; and whoever wishes to pray the Witr with three, let him do so; and whoever wishes to pray the Witr with one, let him do so.’” [Abu Daawood, Ibn Maajah, An-Nasaa'i, and Ibn Hibbaan]
The Kuwaiti Encyclopedia of Fiqh reads:
“The manner of performing the Witr prayer:
First: Fasl (separating the Rak‘ahs) and Wasl (connecting them): a person may pray the Witr with one Rak‘ah or three or five or more:
A) If he prays the Witr with one Rak‘ah ... then it is clear how to perform it.
B) If he prays the Witr with three Rak‘ahs, then there are three ways to perform them:
1. The first way: to pray two Rak‘ahs and recite Tasleem and then perform a third Rak‘ah on its own with an independent opening Takbeer ... based on the hadeeth of Ibn ‘Umar, may Allah be pleased with them, in which the Prophet, sallallahu ‘alayhi wa sallam, used to separate the two Rak‘ahs (of Shaf') from the single Rak‘ah with a Tasleem. It was also reported that Ibn ‘Umar, may Allah be pleased with them, used to recite Tasleem after the two Rak‘ahs and ask (his household) for something he needed.
2. The second way: to pray three consecutive Rak‘ahs as one unit without separating them with Tasleem or sitting...
3. The third way: to pray three Rak‘ahs by sitting for Tashahhud after the second Rak‘ah without Tasleem, then standing up to perform the third Rak‘ah, and then recite Tasleem after the third Rak‘ah. Thus, the Witr prayer, in this case, is similar to the Maghrib prayer; however, unlike the Maghrib prayer, he recites a soorah after the Faatihah in the third Rak‘ah of the Witr...
C) Performing more than three Rak‘ahs:
...The Shaafi‘is held that it is better to recite Tasleem after each two Rak‘ahs, based on the hadeeth: “The Prophet, sallallahu ‘alayhi wa sallam, after praying the ‘Ishaa and before the Fajr, used to pray eleven Rak‘ahs, saying the Tasleem after each two Rak‘ahs, then praying the Witr as one Rak‘ah.” He may also perform four Rak‘ahs with one Tasleem, then six Rak‘ahs with one Tasleem, and then perform one Rak‘ah on its own. He may also perform these Rak‘ahs with one Tashahhud or two Tashahhuds in the last three Rak‘ahs.
The Hanbalis held that if he performs five or seven Rak‘ahs as Witr, it is better to perform them all as one unit and recite one Tashahhud at the end, based on the hadeeth of ‘Aa’ishah, may Allah be pleased with her, who related that the Prophet, sallallahu ‘alayhi wa sallam, used to perform thirteen Rak‘ahs of night prayer. Five out of them were Witr, and he did not sit except in the last Rak'ah. Moreover, Umm Salamah, may Allah be pleased with her, narrated that the Prophet, sallallahu ‘alayhi wa sallam, used to pray the Witr with seven or five (Rak‘ahs), not separating them with Tasleem.
If he performs nine Rak‘ahs as Witr, it is better to perform eight consecutive Rak‘ahs, then sit down to recite the Tashahhud without Tasleem, then stand up again to perform the ninth Rak‘ah, and then recite the full Tashahhud and conclude the prayer with Tasleem. It is also permissible to recite Tasleem after each two Rak‘ahs when performing five or seven or nine Rak‘ahs as Witr.
If he performs eleven Rak‘ahs as Witr, it is better to recite Tasleem after each two Rak‘ahs. It is also permissible to perform ten consecutive Rak‘ahs as one unit, recite Tashahhud, then stand up and perform one more Rak‘ah, and then recite Tasleem. It is permissible to perform the eleven Rak‘ahs as one unit without sitting for Tashahhud except in the last Rak'ah...” [Summarized]
It is recommended in the Witr prayer to recite Soorah 87 (Al-A‘la) in the first Rak‘ah, Soorah 109 (Al-Kaafiroon) in the second, and Soorah 112 (Al-Ikhlaas) in the third. It is also recommended to say after Tasleem: 'Subhaan Al-Malik Al-Quddoos (which means: Glory be to the Sovereign, the Most Holy).'
Ibn Qudaamah wrote:
“It is recommended to recite the following Thikr (expressions of remembrance of Allah) after performing the Witr prayer: 'Subhaan Al-Malik Al-Quddoos' thrice, extending one's voice the third time. Ubayy ibn Ka‘b, may Allah be pleased with him, reported that the Messenger of Allah, sallallahu ‘alayhi wa sallam, used to recite after Tasleem in Witr prayer: 'Subhaan Al-Malik Al-Quddoos.' [Abu Daawood] ‘Abd Ar-Rahmaan ibn Abza said, 'The Messenger of Allah, sallallahu ‘alayhi wa sallam, used to recite Soorahs 87, 109, and 112 in the Witr prayer, and after reciting Tasleem, he would say: 'Subhaan Al-Malik Al-Quddoos', raising his voice with it in the third time.' [Ahmad]” [Al-Mughni]
Allah knows best.