An orphan and I prayed behind the Prophet (may Allah's peace and blessings be upon him) in our house, and my mother Umm Sulaym was standing behind us

Explanation

Anas (may Allah be pleased with him) relates in this Hadīth that the Prophet (may Allah's peace and blessings be upon him) led him and an orphan in prayer, and the two of them were standing behind him. He also informs that his mother, called Umm Sulaym, offered the prayer behind them. So, the rows were as follows:

The Imām stood at the front.

The boys, Anas and the orphan, stood behind the Imām.

The woman, Umm Sulaym, stood behind them all.