Please Help with interactive material change on static mesh

I lost myself inbetween nodes./ I used classic trigger box changing color system, but i want to switch to other system. I created blueprint which use LineTrace and add HIGHLIGHT over object which im aiming. Problem is that I cant force the mesh to change color after click(or show colorpicker and add color). I dont know how. Please anybody—can you show me the way? Some general thinking or some concrete blueprints?

Thanks a lot