Mock up

I have bought the IB-7, 7 String Electric Guitar Kit and I'm not entirely sure how far to go with the mock up. Should I be drilling screw holes and actually screwing everything in to see how it all fits before the sanding and finish, or should I just put everything in and let it rest in it?

Attachment 16007
There are also a couple of things I'm not sure where to put or what they are for. I have some idea but I want to be absolutely sure. Thanks.

Hi Jack welcome to the forum. Up to you if you pre-drill holes before or after the finish. Main things to check are all the parts are there and the neck fits in the pocket nicely.
In the photo bottom right are the bridge pivots for the floating tremelo, top bits would be for the locking nut, that is a tiny bit of solder and the nut and washer are probably for a potentiometer maybe

I probably wouldn't screw everything in as a first step - check out http://www.buildyourownguitar.com.au...ead.php?t=5541 for some tips on the mock build.