Clear a square or line for another piece.
A clearance move gets your own piece out of the way. Another piece can then use the square, file, rank or diagonal. If you sacrifice the blocking piece, the follow-up must justify the material you give up.
Bring your knight into the attack with check
Your knight gives check, so the opponent must answer it. In this continuation, your queen gives the final checkmate.
2 more clean runs (at any point) to reach Recall.