Answered by Shaykh Faraz Rabbani
Do you stand next to the iman, one foot length behind the iman or a whole row behind ,if only two people are in the congregration?
Walaikum assalam wa rahmatullah,
The sunna for one person praying behind the imam is to pray next to him, on the right, almost level (but with heel just behind his heel).
And Allah alone gives success.
Faraz Rabbani