If you go to this page: https://brotherly.itch.io/the-come-up
If should say that you own the game at the top and there should also be a download button there. If you click that, at the top, there should be links for the Non VR and VR versions.
If you have the itch app open, it should, if I read it correctly, just update/download a patch for the game automatically. If you start a new game there is a cutscene right at the beginning of the latest version.