Hi Klawkins, what VR platform are you using? Once you pick up the brush you have to dab your paint pallet to select a color. Then you should be able to hold down the trigger in the brush hand to paint. If that doesn't work try setting down your brush by placing on pedestal and picking it up again. If that still doesn't work please let us know so we can look into it!
Ah I should have mentioned first that I was using a Samsung Odyssey+ (WMR) headset to launch the game. The headset is supposed work with SteamVR, but I wouldn't be surprised if its controllers handle a bit differently so perhaps it might not be compatible.
Aside from that though I didn't move the executable. I'll be sure to give it another go tomorrow to see if I can get the trigger working. Thank you for the help!