Hello. I've installed Kavita docker on my UNRAID, started adding books, and I have realized I don't like how Kavita sort them, deleted all, but now when I add the books on groups Kavita doesn't add them, how can I resolve this. I've uninstalled the app, deleted the app folder, but doesn't like it

Check the description of how the scanner of kavita expects that the library is set up on the kavita wiki. 

I use it for magazines as well and had to define d-m-y in each filename in order that the scanner groups it together in the way I want. 

You can also create a PR on github for your use case I guess. 

Kavita organizes off of metadata for books and light novels and by filename for comics and manga if that helps.  You may need to use sigil or calibre to edit the metadata for your books/light novels.