How to make an interactive HUD button

How do I make an interactive HUD button, which when clicked it changes the diffuse color of specified shader to a random color value?

Hey,

have a look at UMG UI Designer. It’s quite simple and easy to pick-up: https://docs.unrealengine.com/latest/INT/Engine/UMG/UserGuide/index.html

Here is also a quick start guide: UMG UI Designer Quick Start Guide for Unreal Engine | Unreal Engine Documentation

I wouldn’t mind helping out further if you require more in depth help, but I hope that this will lead you in the right direction.