16. Rb1+ ... While black may be worried about its queen right now, Rb1+ will win the white queen and will even allow black to keep their queen. Analyze all possible white responses to the check. If Ne1, then Rxe1+. If Bf1, then Qxc4 since there is a rook pin on the bishop. There are no good options for white. The white queen is lost.
17. Ng3 ... This move forks the queen on e2 and the rook on f1. White can not play Rxg3, do you see what will happen if they do?
18. Rb3 ... White is forced to move thier knight but there is no good spot for it. If white plays either Na2 or Nc2, the knight will be lost after black responds with Rb2 or Rb2+. The knight must play away and once it does, black pushes the a4 pawn to advance towards queen-hood!