This screen gives you the list of already recognized repositories. You can add other sources for packages, like an optical disc or a remote source. The source selection determines which packages will be available for selection during the next steps. For a network source, there are two steps to follow: Choosing and activation of the network, if not already up. Selecting a mirror or specifying a URL (very first entry). By selecting a mirror, you have access to the selection of all repositories managed by Mageia, like the Nonfree , the Tainted repositories and the Updates. With the URL, you can designate a specific repository or your own NFS installation.