In-Game, if you move your mouse all the way to the right of the screen, and the app sidebar will appear
At the top , if you click the square icon in the top right, it will open the list of apps
You can search using a filter bar at the top of the opened app list, if you like.
Find and open App Shelf. There are quite a few CSP built-in apps you can activate , as per the image below:
Some very helpful apps are:
Radar - easy to use and configure car radar for seeing other drivers' cars
Rally Copilot - Adds turn markers and pace notes, emulating popular rally sim games
Dynamic Return or Time Shift - Lets you go back in time to retry a section of the track quickly (not usable in online races)
The Setup Exchange - Gives you access to a car setup exchange in the Pits Setup menu to download or upload setups for your car/track
Car Mirrors - Lets you adjust your cockpit mirrors (angles, FoV, etc). Not useable with the default Virtual Mirror