This has been asked like 50 times...here's an example of a recent one:
http://forum.thegamecreators.com/?m=forum_view&t=61538&b=21
anyway SkyCubes explained it greatly in the other post:
Quote: "1. Go to 'File' then click 'Build Game'.
2. Click the 2nd tab from the left labeled 'Level Settings'.
3. Click the 2nd button from the top-right labeled 'Edit' (Global Script).
4. In the 2nd category labeled 'Level Setup' click in the white-box area to the right of 'Sky'. Once you click inside that area, you'll see a little browse-to button with 3 little dots. Click that button and browse to one of the 5 skycube folders.
5. Inside each folder are subfolders. Click on one of the sub folders and look for the .x file. Select that file to apply that skycube"
=-{SKaleX}-= Current Projects: -Insane Killer-=-Chaos Zone-