Against a rook pawn with the enemy rook in front of it, put your rook on the pawn's rank and attack it from the side. Their rook is then stuck guarding the pawn, and their king can't come to help without walking into checks from the side. Keep your own king on your second rank on the far side, away from the corner the pawn is heading for.
Every move is checked with an endgame tablebase, which knows the exact result of every position with up to seven pieces. The computer defends perfectly, and if a move throws the result away, the trainer stops and shows you a better one.
