I'm not a professional installer, carpenter, or electrician, and I did not consult any pros. I probably use some incorrect terms, and there are probably things I could have done differently, but what I did worked for me. Be sure to take all safety precautions, and use common sense, and of course don't blame me if you screw up.
Step 1: Getting Started
Step 2: Choose Placement
Mark the locations with a piece of masking tape or a pencil. You want to place your speaker jack close to the speaker, but you need to check for studs with the stud finder. I got pretty lucky, only one was close to a stud, and I only had to move it about 1/4" over to clear it. Mark your faceplate locations with the pencil in the screw holes.