Once a person asked Allah's Messenger (ﷺ) (ﷺ) about the night prayer. Allah's Apostle (ﷺ) replied, "The night prayer is offered as two Rak`at followed by two Rak`at and so on and if anyone is afraid of the approaching dawn (Fajr prayer) he should pray one Rak`ah and this will be a Witr for all the Rak`at which he has prayed before."
Sahih al-Bukhari Book 14, Hadith 1
← Previous Hadith The Prophet (ﷺ) went out and offered a two rak`at prayer on the Day of `Id ul Fitr and did not offer any other prayer before or after it and at that time Bilal was accompanying him.

Sahih al-Bukhari Book 13, Hadith 37 Next Hadith → Nafi` told that `Abdullah bin `Umar used to say Taslim between (the first) two Rak`at and (the third) odd one in the Witr prayer, when he wanted to attend to a certain matter (during that interval between the Rak`at).

Sahih al-Bukhari Book 14, Hadith 2