The Messenger of Allah (PBUH) used to begin the prayer by doing At-Takbeer and reciting {Praise is due to Allah, Lord of the Worlds} [Al-Fatihah: 2], so when he bowed, he did not raise his head up nor lower it down, but in between. When he raised his head from bowing, he would not prostrate until he was settled standing upright. When he raised his head from prostrating, he did not prostrate until he was settled sitting. In every two rak’ahs he would recite (At-Taheyyat). He disliked spreading his arms like wild animals.He used to lay his left foot down, put his right foot upright, and to forbade sitting on heels like devils, and he ended the prayer with a At-Tasleem.

It is a Sunnah of prayer to lay your left foot down and hold your right foot upright.