@kaio thank you so much for your help. I also struggled a lot after your last response but I was able to finish the addon, here is how it looks now:
I wouldn’t have done without yout help. Thanks again.
I also published it into my github page. I believe this is not very useful because it is focused to new users and I think they would not know how to install it. But I would like to leave this idea in case the Blender developers want to implement this as a native tool for new users.