You probably just popped the spring off the slider switch, jimbobuk, it's not that difficult to get back on (as long as you didn't actually break anything

), just a little finicky is all.
As for taking it apart. You'll need to remove all the screws you see on the outside (including the bottom edge), and the ones you see in the card slot. I think one of the disassemblers who posted pix described that in some detail.
The only really tricky part about putting it back together is getting the screws near the magnets back into their holes, the magnets want to grab them away, you see. Needle-nosed pliers are a big help there.