Ok so first of all this exercise was designed to show that sometimes a seemingly strong move (i.e. e6+ followed by discovered attack on the queen and taking the queen) although it seems VERY appealing can be a blunder.
So the mate line is:
Irrelevant move by white but say Qa6 Rxa6
Irrelevant move by white (say b4) Ra1#
Now, if white plays f3 and say bishop retreats to g6
Qb5 (threatens to fork King and rook) Kf7
and then, either the rook will have to leave the a-file which means the queen is gone or move between a5 and a8 which means the black pawns are gone with an eventual
Qb7+ and the black queen is gone
So for black it is best to sacrifice the Bishop after
Kxc2 and moves the blac queen out of harms way with a check
e4 (black moves queen out of the way but loses bishop)
So in conclusion, the stronger move for white, (assuming perfect play from black) is to win the bishop. After that of course the game is even easier for white.
Anyway, so that was a first attempt at an chess puzzle. I guess it was a bit out of the ordinary (mate in n moves or find the ! move). Of course white could play many ok moves (since he was in better position) and eventually win, but the best one to win material is the short run is f3.
I'll try again with a more conventional puzzle in the future