Hey Shapeshifter,
1. In-editor, make sure that in the menu bar under Level > Edit level data... you have "Is Game Master Level" set to True in the
Level Settings Window 2. If you made an add-on, be sure to have it enabled in the settings of the GM Campaign, as shown
here.
3. If you made an adventure, be sure to have a dependency on GM. Else you'll have to set up scripting yourself and enable the adventure in the campaign settings as explained
here. For just adding levels, I suggest an add-on.
