This - how to play chess exercise1 - teaches you to win your game, when you are up in material. Win this position below playing it versus the chess program.
You are White and will get a decisive material advantage next move, and from then on you are supposed to win this game. If you can't win this position then try this chess exercise until you can.
I give you a few hints. If you have a big material advantage like being a piece up in an otherwise equal position or you have won an important pawn or more in an equal position, then try to trade off as many pieces as possible to simplify the position and go into the endgame where you will be up in material and should win without major difficulties. In the endgame your advantage in material can be realized so much easier as the position is much more simple and there is usually no danger for the king as most pieces are off the board. So your king becomes actively involved in the chess struggle and chases pawns and helps your pieces to win.
For example, let's say you have won a bishop. (this means you are a piece up) Now if you trade off all pieces like queen, rooks, knights and bishops, you will have king, a bishop and pawns in the endgame. But your opponent has just the king and pawns! You have much more power in the endgame. So your bishop or your king will capture his pawns and then you promote one of your pawns into a queen and win easily. But make sure you still have a pawn left to promote, so don't trade a pawn if you have just one pawn left because after that you have no pawn to promote.