Three pawns against two on the same wing is a draw with correct defence: keep the rook active behind or beside the enemy pawns, keep the king in front of the pawns, and avoid weakening pawn moves.
A typical practical structure: White has f2, g3 and h4 against Black's g6 and h5, with the kings nearby. This is a theoretical draw, but it has been lost thousands of times in practice. The defender's plan has three parts.