The Host permissions page controls permissions specific to hosts themselves, if you wish to give an additional user permissions to hosts on your domain you can either give them full control of the domain (not recommended), apply these permissions specifically to each host on an as required basis, or using the tab under the current permission holders box, apply permissions to all hosts.
Host permissions are broken up into the following:
Show Authorised Users: Shows users who currently have permissions specifically for this host
Search by Name: Allows you to search for a user to grant permission by name
Search by Email: Allows you to search of a user to grant permission for this host by email address
Once a user has been searched for and selected, you can then attribute settings specific to that user. The type of controls that can be applied are
No Access - Doesnt apply any access for the user
Read only - Grants access to the user to see all current settings applied to a host, however the user can not modify any settings a host has.
Write - Give user access to make changes to the host, including change configuration settings, and more importantly install game software to the host