In order to win this kind of endgame(king+rookpawn+wrong color bishop vs king) you can't let the oponnent's king reach the corner were you promote the pawn. If you are on the defensive side, you only need to get the king to the corner and that's a draw! There are several cases that you just can't win this endgame but in the following cases you can try three different maneuvers.
This second puzzle is very similar to the first one. Lets see if you can figure it out.
Here is another exemple were you have to cut of the king from the a8 square (please check the variation by clicking on the question mark)
At the end of the day you are starting to get the picture of this kind of endgame. You need to creat a barrier so that the enemie's king can't reach the corner.