A man who lived in the desert asked the Messenger of Allah ﷺ about the prayer at night. He made a sign with his two fingers-in this way in pairs. The witr consists of one rak'ah towards the end in night.
أَنَّ رَجُلاً مِنْ أَهْلِ الْبَادِيَةِ سَأَلَ النَّبِيَّ ﷺ عَنْ صَلاَةِ اللَّيْلِ فَقَالَ بِأُصْبُعَيْهِ هَكَذَا مَثْنَى مَثْنَى وَالْوِتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ