It doesn't help that the editor is kind of arcane, and I haven't had much luck figuring it out. Is it possible to add a user data set that sits alongside this? Say I wanted to create my own "sourcebook" of third-party options that I allow in-game?
If you have a game system that you own (in this case, if you have the Authoring Kit purchased, you will have base Savage Worlds available to you), the help menu includes an entry for using the editor, which is useful.