To install a new Update Site:
You need to fill in the name of the feature (the name is free) and the location of the Update Site.
On a local repository, click on Local… and select the folder to use as Repository (the unzipped Update Site)
On a Zipped Update Site, click Archive… and select the UpdateSite.zip file to install
Select the Repository and select the Feature(s) to Install
Validate the Summary of what will be installed
You can be asked to accept license agreement