I used to have a template (with css and js) that can be used as PWA, with offline caching and all that stuff. I copy most of the stuff from Google itself, but I

I used to have a template (with css and js) that can be used as PWA, with offline caching and all that stuff. I copy most of the stuff from Google itself, but I never found their explanation that great. I wish there was a guide for it too