Support or attack a passed pawn from behind.
A rook behind your passed pawn can support its advance along the file. Behind an enemy passed pawn, it can maintain pressure as the pawn advances. This is a useful guideline, but king safety, promotion threats and active checks can require another square.
Advance your pawn toward promotion
Your passed pawn is 3 squares from the last rank. In this line, it keeps advancing and becomes a queen.
2 more clean runs (at any point) to reach Recall.