Hi there, I am new using Anki. This month I created a few decks, then a friend sended to me hers decks so I wanted to add them in my Anki, but since I did it I lost my decs and I have only the ones that I have Imported. How can I have back my decs?
You can restore from an automatic backup to get your own decks back. Restoring an Automatic Backup (Recovering from Data Loss) - Anki FAQs
Is it possible that your friend sent you the decks as a colpkg file – Exporting - Anki Manual? Importing that is meant to replace your whole collection. Can you get her to send it to you as an apkg instead? If not, you can turn it into an apkg yourself, but there are a few extra steps.