1. a3 followed by 2. b4 to create a passed pawn. The black king is overloaded; he cannot manage both sides of the board. One pawn will promote to a powerful queen.

1. ... Kf6 with the threat 2. ... g5# (and white had to sacrifice the rook or the bishop).

White is in check and must do something about it. The white queen stays where she is to maintain the threat on both bishops. Knight on d1 doesn't work because then the white queen is tied down defending the knight. Bishop on f1 doesn't work because Qxe4 threatens checkmate on h1. Therefore, the best move is Knight on f1. And White wins one of the two bishops on the next move, gaining a significant advantage.

I think 1. ... Re8-e2. Threatening to take on f2, nothing white can do against it, execpt giving a Rook with 2. ... Rd2

The black Knight on f6 is under attack. Only way to protect it 1. ... Qd8 doesn't work because of 2. Nc6. If black moves the knight, 2. Qg8# is the thread. So only possible move for black in my opinion is 1. ... Nh5 --> Save the Knight and protect g7 from getting mated.