>>383797761
>>383797979
Double click on the scene file (one that looks like the unity logo) and it should pull up the scene that's been preset with the avatar already set up.
From there all you need to do is upload it.
>>383798306
This is already set up on most models. You're making the whole thing more complicated than it has to be. Just upload what you have, see how it works, then think about where you want to modify it.