Follow the 4 Steps (look at the images) =
-1° : Download the avatar (avatar folder inside the RAR)
-2° : Open the Folder with the correct Unity version (look at the example in the images)
-3° : Log in with your account
-4° : Upload the avatar
yo bois I've returned bringing to all of you the avatars that I made years ago
Remember : This Unity proyect must be open in Unity 2018.4.20f1