I know this isn't a revelation to the old timers, but new people get their first compact Mac every day, and they come to this forum for help, so:

The screws on the back of your compact Mac need a Torx #15 driver with at least a 6 inch (15cm) long shaft to get to the under-handle screws.

Unless you have a very complete tool-set, you will probably need to buy one. Stubby T15 bits in extenders tend not to work, because the extender is usually too big for the small inner-diameter wells the screws are at the bottom of under the handle on the top of the Mac.

You can get the long bit that's usually on eBay for $4.50+shipping, or you can walk in and get a screw-driver shaped one at Sears for $6.29 (prices at time of posting).

A vital (and cheap) addition to your Mac toolbox.