There are three (3) ways to install tracks into Gp4.
1. Copy and paste the dat file into the circuits folder and the wad file into the root of your Gp4 installation.
2. Use Gpxpatch (Gpxtrack tab). Basic Tutorial: [
www.mediafire.com]
3. Use TSM to install. I can't help you with this as I do not use csm/tsm.
Most mods do not include a trackpack. There are a few though, 88, 91, 94 - 99.
You could look at the gp4database which has many tracks available.
Glenn (Cdn)