Yes you can call the script backup.sh and for security reasons put it below public_html. The script needs to be executed on the “shell” and not via a browser. If you have access to your hosting provider shell, then you can run it via a scheduler (eg cron). If you don’t have access to the shell ask your hosting provider if you can be given access to cron. Most hosting providers have some sort of a Control Panel do upload/add schedulers. Let me know how you go.

or what?
Where do I upload it?
public_html or bellow?

Thanks Heaps
Shaz
Sorry if obvious, I am a learner