The Galaxy Forge-made custom maps should go into the your "GalaxyForge" folder in your Application Data or AppData folder. That is the right place.
What exactly is the problem? When you save in the GalaxyForge folder and then load the game, the game never sees or acknowledges the files? Are you on the most recent version of Galaxy Forge? (If you open up the map files with Wordpad, does it say "versionNumber 3"?
