It’s recommended to install the plugin for the engine from Unreal Marketplace. This way you don’t have to install it separately for each project.
Installing Varjo OpenXR plugin for Unreal Engine
Open Epic Games Launcher and go to Unreal Marketplace tab.
Open Varjo OpenXR plugin Marketplace page. Click Free and then Install to Engine.
Select the engine you want to install the plugin for and click Install.
The plugin is now installed for your engine. Open a project and you can see the installed plugin in
Plugins. Enable the plugin and restart the project.
Continue following the steps in Getting Started with Unreal.