You sorta have to do some of the panel stuff at the same time; specifically those little triangle pieces at the rear corners of the door opening and the strip that goes up the door. If I remember correctly, those are the only two panel pieces that need to be installed before the carpet.
After that, start on the back shelf first. Do the "lump" thing first. You will have to trim, so fit and trim all the shelf under felt then glue. After that do the shelf carpet in the same order. Pay special attention to the "lump" and make sure that it doesn't have any wrinkles in it...especially with the under felt.
After the shelf, trim the under felt for the floor and lay it in place, but don't fasten it down yet. Next, I did the door sills. Definitely test fit that stuff using the weatherstripping first before you cut or glue! It's a pretty tricky fit around those triangle pieces.
Glue the firewall piece now. I would lay in the floor carpet just to make sure that you cover everything before you trim this piece.
The tunnel comes next. I only glued the top part on the brake tunnel, that way, if needed, I can remove the tunnel without ripping the carpet. For the trans tunnel, I glued the under felt, but snapped in the carpet, just like the front floor carpet. It makes gearbox maintenance a little easier.
Now is probably a good time to install (or at least test fit) the trans tunnel brace better known as the center console. That thing is a pain to get installed with new carpet.
Finally the floor pieces. With all the other carpet in place, fit the snaps to the floor pieces. Cut 2" holes in the under felt and install the snaps on the carpet. Remove the mounts off your seats and VERY carefully, bolt down the seat tracks. Install the seats now.
Hopefully I didn't miss anything. I used 3M super interior adhesive. That stuff rocks!