There are a few tricks to drawer slides. The main things to get right are to make them parallel and co-planar (same distance from the case bottom on the right and the left side, as well as level front-to-back in the case). It helps if your case is perfectly square, so really focus on that. You'll want to determine your drawer width based on how thick the slides are.

A good rule of thumb is to always try new drawer hardware in a scrap case to get a feel for how it works. That way you'll work out any issues and not-so-obvious dimensions without having to fill in bad screw holes on your real project.

Here is a brief blog post on some Kreg jigs that assist in this process, and here is a YouTube video on how to do it using just spacer blocks to get everything flush and level. Here and here are some succinct points to follow and another good video. And last but not least, a good article on Rockler's site with some recommendations for jigs that ease the process.