It is worth noting that actions undertaken by smart rules and scripts cannot be undone. A smart rule like this could pretty much ruin the best of days:
I have set up a test database for trying things out. I also make regular backups of my databases.
Play with automation in a safe environment; if in doubt close any databases which are important. And when you get stuck, come back to the forum, ideally post screenshots of what you have set up and explain what you are trying to achieve. And ppl will help 