https:///mixer/interactive-unreal-plugin
This is an integration of Mixer Interactivity 2.0 into Unreal Engine. The plugin is designed to help you associate your Unreal project with your Mixer Interactivity project, provide some building blocks for signing in at runtime, and allowing you to handle input from viewers of a stream in Blueprint very much like local input.
for some help on getting started, and please let us know how you get on here or using our Issues page.