Whites checkmate luck

A puzzle which black makes a big blunder.can you figure out his blunder a achieve victory?( To all chess.com members looking at this puzzle, Black makes a big blunder during the moves so be extra careful!)

There is no point in taking the rook cos it is checkmate. 

hey NZ, enjoy fall later this week

nice

ha, I thought I was getting worse at chess b/c I couldn't see a checkmate 

Luckily that is not the case, black misses the only defense with 1...Ne7. 

true

I knew that  anyway.That WAS the big blunder

lol i thought that too. lllllloooooolllll

can anyone explain why black moved the pawn and not the knight to attack the bishop?

edit: lol i didn't read the explanation of the problem on the side