If you’ve gotten yourself in a situation where things are already broken, you should restore from an automatic backup before you started making changes – Restoring an Automatic Backup (Recovering from Data Loss) - Anki FAQs .
I’m not going to make you a demonstration video, because there are tons of those out there you can already find yourself. There are probably even videos in Portuguese that you could find. But, as BenJamesBen said – none of that is going to help you if you don’t take a few minutes to understand those key concepts of Anki, so you know what you’re editing and why.