You will need to clone the repo using GitHub desktop or a similiar tool, since using the download zip button does not seem to download all the files properly.
Import PolyToolkit from the Unity Asset Store.
(Optional) Import ProBuilder from the Unity Asset Store.
Select Poly in the file menu, and click browse assets. From there you can search for 3D models to import into your project. See the Wiki for other sources
Click File - New Scene, and drag in the Room prefab from the Prefabs folder. Then drag in the [VRTK_SDKManager] prefab and the Controllers prefab. Set the Right and Left Controller variable of the [VRTK_SDKManager] to the controllers you just made.
By default, VR-Educational-Toolkit uses SteamVR, which supports a variety of PC-based headsets. However because VRET uses VRTK, it is easy to add support for other SDKs. See here for setup info.