How can i get an edge in this position?
You can trade bishops and take the a7 pawn as one idea.
EDIT: You're black. I don't know that you can take an edge.
I fast forwarded to the end position not seeing it was black's move and played Bxf5 gxf5 Bxa7. The queen can't take because of the weak back rank.
For black, I'm not sure you can take an edge. I think white is better.
I think you are right, but why book says Bf5 is slightly better for black?
Personally I can't see why black would be better.
EDIT: please_let_me_win beat me to it
Thank you guys! Appreciated!
There was a very recent public votechess game, with that exact same variation. You might look that up.
But I think taking that rook on a8 is a mistake for white. If he wants to win, anyway.
If you're black you're at a disadvantage. You can't get the advantage right off the bat, but I like to just take my knights in & out and try to gobble up their pieces if they get too aggressive, catching them off balance.