This is a badly developed knight.

defending the bishop and pawn, which is actually unnecessary at this point.

developing the bishop to allow castling.

castling kingside is now impossible

alternative is to move the king. h2 is lost anyway. Moving the king to the 2nd line would immediately defend the rook (see later).

This attack is premature. Development of pieces and castling is not yet finished. The attack can't result in mate.

Be3 defends the rook.

B is now also under attack. But the N is unsecured and is lost now.

This allows the rook on g1 to attack the Q. It shouldn't be hanging there (anymore)...

Why was I leaving the queen there?