I am very new - how is this checkmate?
- no squares to walk away
- no possibility to take checkmating piece
- no figure in from of your king to protect against check
Review all these 3 points and you will see its checkmate
There is no bishop on a1. Even if there was one, it wouldn't matter one bit.
There is very important bishop at c5.
There is no way to tell what the real question is. Maybe the OP missed the c8 bishop, maybe the c8 bishop, maybe the OP doesn't know how the bishop or the queen moves, or what "checkmate" is. Who knows?

Took it out because I realized what I didnt see - I cant figure out how to delete this entire thread - sorry