Can't update my VRChat world in Unity

So when I hit build and test, the world will run perfectly. However when I try to build and publish (to update my world) it just says unity application is running, and plays the scene in unity. I’ve only uploaded my world once, and this is the first attempt at updating.

 

Okay so I seem to have fixed this issue, and it now goes to the upload page. However it’s going to the page where you upload a new world, and I’m trying to update my existing world. Any help is very much appreciated!