There is no tutorial but it is not difficult. You need to install the "REI3 Repo" application on another r3 system - one that your regular r3 systems can reach. You create a user with the role 'Public access' that serves to authenticate requests.
You then change the repository details (host, user, password) inside the admin panel (System->Application Repository) of your regular r3 systems to the details of your r3 system that hosts the "REI3 Repo" application.
To release application version, you need to register your app & export files in the "REI3 Repo" application.
Downside of hosting your own repo: If you use our public apps, you need to release these in your local repo as well. This can be useful though to control which versions your r3 servers can even receive.
