The guide to the Unreal Layer Sample states thie following: Actor_Blueprint illustrates rendering a UMG widget into a stereo layer. The widget is first rendered into a Material, then the SlateUI texture is pulled from the Material into the stereo layer. This is the UMG widget that is rendered to the quad and cylindrical layers in the sample.
But there is not blueprint code inside the Actor_Blueprint of the sample project. The Event Graph is completely empty. The two stereo layers in the level only show a texture which was manually set and not the sample UMG widget called MenuBlueprint. This is from the gitHub Oculus Samples. @NinjaGaijin maybe you know what is happening here?
I just came across your post because I, too, don't see enough supporting code for this example to work. The cat texture specified in the stereo layer shows on both Actors that have Stereo Layer components, but there's no evidence anything is happening with the Widget Blueprint in the Actor_Blueprint for it to be able to render the result of the widget to the screen. The Material used in the example appears to be default/blank, so there's no obvious understanding how this stuff works.
Actually, I just figured it out. I haven't played around with what the material is actually doing, but you can use the following to get the UMG widget to render to the screen. I have tried this with and without Live Texture on, but not when updating the UMG widget. If your UI isn't updating, you can probably do this just once after a slight delay instead of on Tick like I'm doing here.