In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
The person praying with the imam the (ma’umum of follower) should be on the right side of the imam (the prayer leader), and exactly on his side, not a step back.
Sheikh Waleed Basyouni elaborates more on where the ma’mum should stand in this video:
Almighty Allah knows best.