HowTo: AddOn dependencies ->
https://www.esoui.com/forums/showthread.php?t=9149
The addon help/support section features some sticky posts (at the top) about the often asked topics, just read them and you'll understand most of the things about addons:
https://www.esoui.com/forums/forumdisplay.php?f=164
The ESOUi wiki also provides more
technical background if you are interested in:
https://wiki.esoui.com/Addon_manifest_(.txt)_format
https://wiki.esoui.com/Libraries