Well, not quite "everything", but enough to help create a script, deploy it, update it and approve permissions for it, to begin with. Of course, there is the official documentation: Google Apps Script
First two guides to deploy a google apps script, standalone and one that is bound to a spreadsheet:
Second a guide to update your google apps script to a new version after editing the script:
Third a guide to correctly reviewing permissions for a script (this is also covered in the second guide above):