White to play and mate in 10. Before moving pieces, try to fully visualize the mainline.

1...Ka1 (or 1...Kb1) leads to 2.Qb2#. 1...Ka3 leads to 2.Qb2+ followed by mate. Hence, Black plays 1...Kb3. Now how do you proceed?

2...Ka4 obviously runs into Qb4#, so Black goes 2...Kc4. How does White proceed?

What happens if Black goes 3...Kb5 here?

Now if ...Ka6, how does White mate?

Back to the mainline: Black plays 3...Kd5 (instead of 3...Kb5), continue with the best move for White.

Black goes 4...Ke4. Is the black king escaping? White to play, find the only move!

Well, Black captures the queen, he has to, how does White continue from here?

Black plays 6...Kg6 (forced). How should White proceed?

Black goes 7...Kg7 (forced). What does White play?

Black plays 8...Kg8. How does White finish off the game?