Oh ok, you walk down the f file just like you were walking across the 6th rank... I guess.
Trouble visualizing

Oh ok, you walk down the f file just like you were walking across the 6th rank... I guess.
Yep black king cant go too far or he is mated. I love the way the black king literally tours the board but cant promote.

Earlier I said mates in 2 can vary a lot in difficulty.
Case in point I found this blog post:
https://www.chess.com/blog/vinniethepooh/check-out-your-mating-skills-by-giving-this-test
A trick I haven't talked about yet (for more advanced mate in 1 or 2 puzzles) is pretend the opponent gets to move first. For a mate in 2 puzzle you'll notice that pretty much all of their moves will allow you to checkmate them... so now you have a big clue for your first move (the clue is don't screw up any of the mates you just calculated and that usually means there is only 1 or two pieces that can be the first move to the solution).
Wait, I didn't solve it for if the black king goes all the way to the g file. If Kg6 then g8=Q+, now I have to rethink it hmm.