I have the following settings.gradle in the root of my Project:
include ':app'
include ':appBookShelf'
include ':appNFC'
include ':appUnitConverter'
include ':appUserPreferences'
include ':libraries:ListViewSwipeActivity'
Please note that I perpend my app names with "app.." to keep them organized, I also have a folder "libraries" where I keep the code of my submodules.
Here is my folder structure: