Problem uploading

when i click build and test it doesnt do anything beside computer making a notif sound and creating another prefab ive tried many thing to overcome this problem but it has also happened with other avis to so im getting highly confused ??

The background of your avatar is blue, this very likely means you’re in a Preview scene and you cannot upload an avatar that is in one of these scenes.
You should be clicking and holding then drag your avatar into the scene, not double clicking on it in your Assets folder.

You can click a small arrow near the top left of Unity to fix this. I circled it red in the picture below.