Added install instructions in package readme

Packages/webxr-input-profiles-loader/README.md

@@ -6,4 +6,17 @@ The package is intended to be used with WebXR exporters in general, and not only
 
 The package uses [glTFast](https://github.com/atteneder/glTFast) to load the models, and Unity's package of Newtonsoft Json.NET to parse the profiles.
 
-You might need to add Shader Variants of the Input Profiles Models to the build for the shaders to work. More info about that can be found at the glTFast docs.
+You might need to add Shader Variants of the Input Profiles Models to the build for the shaders to work. More info about that can be found at the glTFast docs.
+
+## Setting package using OpenUPM
+
+Set a `Scoped Registry` in `Project Settings > Package Manager` for OpenUPM.
+
+```
+Name: OpenUPM
+URL: https://package.openupm.com
+Scope(s): com.de-panther
+          com.atteneder
+```
+
+Then in `Window > Package Manager` selecting `Packages: My Registries` and the WebXR Input Profiles Loader package would be available for install.