Maps can be uploaded from
your server or downloaded from a remote web server. You can upload just
the map file itself or a zip archive containing many maps, and you can
select which maps in the archive you want to add to your map
pool. 



To upload a map click the Edit Maps link on the Instance page for the
instance you want to upload a map to. Scroll down to the “Custom Maps”
section on the next page, click the browse button and open the map or
zip file containing maps to the form, then click next. If the map or
zip file exists on a remote web server you can enter the URL to it in
the field below the file field and hit next. Once

Cortex gets the map it will prompt you to select which maps you want to
upload if you chose to upload a map pack, and it will ask you which
gametypes the map is compatible with if the engine has special gametype
requirements. Once that form is completed the map or maps will be
available in your map pool.