Install a ? clean copy ? of Skyrim VR from HERE. The game needs to be in your Steam library but does not need to be installed.
The Steam edition of Enderal SE is based off the Skyrim SE engine which does not support VR. Note that the ONLY version of Skyrim you need is Skyrim VR.
This guide describes how to configure Skyrim VR to play Enderal: Forgotten Stories SE in VR using Mod Organizer 2.