The Prokes Maneuver demonstrates how important it is to study end games. White has a king and a rook while black has a king and two pawns. The thing going for black is that both pawns are central, connected, and two squares away from promotion. That is significant pressure that white has to deal with, even with the only major piece on the board.
The most important thing for white is to get the king involved in the game. The rook, by itself, is not able to withstand the pressure the black has coming.
It’s recommended that you watch the video below and practice on the section at the bottom of this page to make sure you can play this end game optimally. Both sides can easily lose this game if they do not play correctly.