Hadith 1421
Ibn Umar said: A man who lived in the desert asked the Messenger of Allah ﷺ about the prayer at night. He made a sing with his two fingers-in this way in pairs. The witr consists of one rak'ah towards the end in night.
Hadith 1422
Narrated Abu Ayyub al-Ansari: The Prophet ﷺ said: The witr is a duty for every Muslim so if anyone wishes to observe it with five rak'ahs, he may do so; if anyone wishes to observe it with three, he may do so, and if anyone wishes to observe it with one, he may do so.