Endgame #1

This one is very hard.
The better idea is write out the plan and the deficiencies in black's position
Black is stuck guarding a8 square from promoting, and also stuck guarding the g5 pawn.
Black can not move the king too far from the g pawn and he must also keep the bishop on the a8-h1 diaganol.
A plan would be to promote the a7 pawn. By moving the white king there, and also block the a8-h1 diaganol, preferably on b7 with the knight.
We can start this with 1. Nb5!
Starting an elaborate plan to promote one of our pawns.
Black can only move his bishop with 1.. Bh1 ( or any square that isn't being attacked)
(1.. Be4 would be a mistake as the g6 pawn can wrong now. 1.. Kf5 would also be a mistake due to 2. Nd4+ forking the king and bishop.)
2. Nd4! (blocking the f5 square for the black king.)
2.. Bb7 (the bishop is all white has) (2.. Be4 again allows the g6 pawn to run and lose the black bishop.)
3. Kd3 (now we just move our king towards the a pawn)
3.. Be4+ 4. Kc4 Bd5+ 5. Kc5  Ba7
6.  Nb5 (starting to position our knight to the b7 square) 6.. Bh1 7. Kb6 Bf3 8. Kc7 8.. Bh1 9. Nd6 Ba8
10. Nb7 and now the position is completely clearly lost for black.
10.. Kf5 11. Kb8 (picking up the bishop before promoting)
11.. Bxb7 12. Kxb7 . We promote to a queen and win the endgame.