Campaign map problem

so i've put maps in the campaign folder and they turn blue, (meaning they can't be played)
i've got a trigger to make it progress to the next map but it still says that they are unused.

can somebody tell me what i have to do?

Try importing a different map that you haven't used recently (or converted from .w3m to .w3x).

One time it wouldn't work for me because my maps were corrupted.

tried it, didn't work

is there anything special i have to do to the first map i put on to make it playable during the campain?

Yes, go to the Loading Screen Tab in your Campaign Editor and go to menu Edit--> Add Button (Ctrl+A).
Now in the field File loaded choose your map.

sweet thanks! :)