Training
The source code can be found on github
Restuarant-POS (https://github.com/mtottrup/restaurant-pos-gas)
and the youtube video is at
Resturant video ( https://www.youtube.com/watch?v=ccVBKUUJUYI )
Another training appscript site : Ctrlq.org ( https://ctrlq.org/google.apps.script/docs/overview.html )
Check what others have done (https://ctrlq.org/google.apps.script/docs/add-ons/index.html)
linkedinTraining21901805614389