The best place to learn more about Google Script is the official documentation available at developers.google.com. Here are other places that will help you get up to speed.
- Google Apps Scripts - Snippets by +Amit Agarwal
- Apps Script Starter - Create Google Apps Script projects locally inside VS Code.
- Digital Inspiration by +Amit Agarwal - Google Addons
- Awesome Google Scripts by +Amit Agarwal
- Build with Google Apps Script - Setup a local development environment for Apps Script
- Apps Script Webinars - YouTube - by +Eric Koleda