These instructions are for 2sxc 8+. For 2sxc 7, use these instructions.

1. Make sure you have all the pre-requisites
2. Find the app you want - either you already have it, or get it from the app-catalog
3. Go to the site/zone administration where you see the app-management
4. Go to the app installer, select your zip file and install
   
5. Confirm the remaining dialogs and reload the page. After the page reloads, select/activate the just-added app to see that it works.