Learn Unity Tutorial nightmare

Hi, I'm new enough to Unity to have few solutions apart from wasting hours going around in circles looking for answers. I wanted to learn post processing for VR via this page: https://learn.unity.com/project/getting-started-with-the-post-processing-stack-for-vr And maybe the problem is that I'm trying to run the downloadable files on Unity 2020.3 when the tutorial page asks which version do I have? and 2018 seems to be the highest available version number. i don't know.

Anyway, maybe mistake number two is that I've tried to load it into URP. It does load, but then I have to go to edit>render pipeline>Universal render pipeline>Upgrade materials to URP Materials.

The scene loads, but now the console has three errors which all relate to VRTK. I have V3 already installed. I understand that V4 Beta is available. I'm just struggling to get the tutorial files to work before the learning can begin, it is taking a lot of time with no success. Can anyone help? Thanks