How to mate a king already in the corner with a knight and a bishop? How can white mate black in 4 moves in this position? This might be easy but I am a beginner.

7k/7N/6K1/8/7p/7B/8/8 w - - 1 0
Normally, when mating with bishop and knight, the black king needs to be in a corner of the same color as the bishop. So this is actually the wrong corner, but thanks to the black pawn, it's still possible.

1. Be6 is the first thing I would try, as it confines the king to the corner; with the king on h6 and the knight on g6 it would be mate. However, the pawn will promote too soon (with check) which spoils this plan.

So let's try to move the king first: 1. Kh6 Kg8. Now 2. Be6+ forces the king back in the corner with tempo: 2... Kh8 and now the knight arrives in time: 3. Nf8 h3 4. Ng6 mate.

7k/7N/6K1/8/7p/7B/8/8 w - - 1 0

1. Kh6 (1. Be6 h3 2. Kh6 h2 3. Nf8 h1=Q+) Kg8 2. Be6+ Kh8 3. Nf8 h3 4. Ng6