Sizing question

[mannyv11]

Ok so I just got my SUBC from DavidSW, thing is beautiful but now I need to size it.
I went over to our wonderful reference library where I learned how to take out a link etc. (thank you tools for posting it) My main question is how to I remove the spring bar from the glidelock clasp it seems a little more complicated then my old sub. I'm having a little bit of trouble figuring out what I'm suppose to be removing so I can lay my bracelet flat and work on it.

Sorry if this is dumb it's just my first time even thinking about doing this, and I don't really feel like going to the AD to get it sized seeing as how last time I brought it there the guy destroyed one of my screws and scratched the link.

thanks in advance