Fiqh-us-Sunnah Volume 4, Funerals and Dhikr, Fiqh 4.063A.

The practice of the learned ones has been to place the body on its right side facing the qiblah. The person placing the body in the grave should say: “In the Name of Allah, and in accordance with the tradition of Allah’s Messenger, peace be upon him.” Then he should loosen the shroud. Ibn ‘Umar reported that when a body was placed in the grave, the Prophet, peace be upon him, used to say: Bismillah wa ‘ala sunnat rasulillah. “In the name of Allah, and in accordance with the tradition of Allah’s Messenger or the practice of Allah’s Messenger.” (Reported by Ahmad, Abu Daw’ud, Tirmizhi, Ibn Majab and Nasa’i, who transmitted it both as a mauquf hadith (its chain of transmitters stopping at a Companion), and as a musnad (uninterruptedly from the Prophet himself)).