At the yellow machine, you can only interact with the two buttons labeled “Over” and “Under”, and you need to pull the lever(on the lfeft) first before you can interact with them.
If you’re having issues with rotating the character, you might need to adjust your mouse sensitivity.
As for SteamVR and Steamtours, I didn’t encounter them on any of the systems I tested it might be related to UE4 settings.
Lastly, thank you so much for reporting these issues you’re actually the first person to play my game!