The game isn't on steam, it's a folder with an .exe.
So you want me to add it to steam as a non-steam game first? Might be helpful to include that.
Even if I add as a non-steam game, there is no GENERAL tab for non-steam games. and Use Desktop Game Theater is nowhere to be seen.
I think I will have to seek a refund. You would be wise to update your listing to say it is incompatible with SteamVR or Steamlink