The main thing is to mimic the high level XML structures used by other modules in order to replicate their behavior and potentially work with future data record field changes.
The easiest way is to use a module similar to what you want to end up with (such as bestiary), remove all the details you don't want, and replace with records you do want.
Since much of this is very data entry intensive, people on the forums have come up with their own parsers to automate.
Also, you can export a module directly from an existing FG campaign, if you just want to make adventure data modules. (Which will show up as additional tabs in the sidebar campaign record lists).
Regards,
JPG
