It's White to play. Before White pushes their passers, they must find a way to deal with b1=Q. So, how should White begin?

1.Bd4 b1=Q - Black has queened the pawn. What should White do?

2.Rb2 Qxa1 - Keep going. White must capture the black queen now before it avails itself of too much freedom!

3.Rd2+ Kxd2 - Keep going.

4.Bxa1 Nd3 - How should White proceed?

5.c6 Nxb4 - Here's a critical moment in the game. What is the correct continuation for White?

6.Bc3+ Kxc3 -Keep going.

7.c7 Nd5 - final move?