You can mostly follow the instructions in the SL4A Wiki:
https://github.com/kuri65536/sl4a/tree/master/docs/SharingScripts.md
This is based on the SL4A project template, and builds on the wiki page linked from above.
You can't put folders into /res/raw/, so you have to zip up all the pure Python modules that your script requires, and place the resulting .zip file into /res/raw/ (alongsite script.py). In script.py, you have to add the following snippet before you import any of the dependencies:
import sys
import os
sys.path.insert(1, os.path.join(os.path.dirname(__file__), 'modules.zip'))