This guide will help you create a new project using High-Definition Render Pipeline (HDRP). These screenshots are taken from Unity 2019.1.4f1. Other versions of Unity may appear differently.
Create a new project in Unity and select High-Definition RP from the templates.
Download and unzip Varjo plugin for Unity archive and navigate to assets folder.
Drag and drop three folders (Varjo, VarjoExamples, and VarjoSteamVR) to the Unity Assets folder.
From the Unity assets window navigate to the Varjo > Prefabs folder and drag VarjoUser to the project hierarchy window.
Navigate to Edit > Project Settings > Quality and set VSync Count to Don’t Sync
Make sure that the Virtual Reality Support is disabled under Edit > Project Settings > Player > XR Settings
From the same Player tab under Other Settings, set Color Space to Linear
Now the scene should run with Varjo VR headset.