Kurotori Udon Kart System

Hi Im new to udon and woreked more with sdk2 so this is uncharted watters for me. Im trying to make a simple world with the Kurotori Udon Kart System prefab, but it does not want to work. I have fallowed that one video in youtube, where he just ploped the prefab in the world with the U# and loaded it up and drove around, but in my case I could not interact with the cart at all
here are the links to what im talking about
-kart GitHub - kurotori4423/KurotoriUdonKart: VRChat kart system by UdonSharp
-U# GitHub - MerlinVR/UdonSharp: An experimental compiler for compiling C# to Udon assembly
the vid [EASY] UDON VRCHAT Prefabs | Kart Racing Tutorial & More - YouTube

any tips or help would be greate

My carts worked until I updated to the new version of unity. Same issue here.