campaign editor help

i know this is a stupid question and i should know this but whenever i try to add a map to my campaign the editor says i cant because the map isnt in use and it marks the title in blue? then when i try to test the campaign it says theres no maps. how do i fix this probably easy problem|||You are trying to use the Trigger?

Actions

Game - Set the next level to Maps\MapName.w3m|||Go to the loading screen tab of the campaign editor. Right click somewhere in the Campaign Screen Buttons anywhere and select Add Button. The rest should be clear enough.