Replying to Dynastar px12 JIB binging help PLEASE

Ok, so I spent the last 30 minutes search barring and googling... And I'm sure someone on here will just link me to the answer. BUT, I cant figure out how to slide my binding back for my new boots. It's hardly a diff from the old boots, but the new ones just dont quite fit. I know there's a little button and some kind of metal thing that lifts up on the back of each binding... Still can't move it.

Thanks for the help