The Lucena position is an endgame position named after Luis Ramirez de Lucena and it is one of the most famous and important positions in chess endgame theory.
This theory occurs in Alessandro Salvio's Il Puttino (1634), a romance on the career of the chess player Leonardo da Cutri as it's given. The position shows that White's aim is to either progress his pawn or to take Black's rook.
Because either of these outcomes will give the White the upper hand to win the game. Though the White pawn is moved forward it can't promote to queen as it's own king is in danger.
Therefore White should move in order to make his king safe such that he can promote the pawn to a queen. The following steps will end in making White the winner. Follow the moves in the chess board:
1. Rd1+ Ke7
gets nowhere because Black can charge the White king with checks and White makes no progress. But White has a plan...
2. Rd4 Ra1 3. Kc7 Rc1+ 4. Kb6 Rb1+ 5. Kc6 Rc1+ 6. Kb5 Rb1+ 7. Rb4!
Denying the Black rook any way of hindering the progress of the White pawn. White shielding his king and pawn with the rook in this way is known as building a bridge.
Alternative approaches are no better for Black to stop White from carrying out his plan. This position is very important in endgames as it is a known win and both the players progress the game to finish in this pattern. Play through the moves a few times to get the hang of it.