I wanted an arc reactor for Infinity War so I looked for one and found a good cover but an inadequate LED holder and clear light so I filed my own. The "light" piece should click right in and hold well with pressure or a little hot glue. The lights are held underneath with hotglue and the hole in the back helps with wiring.
This is a basic remix of Telleva's file and this wouldn't look nearly as nice without his work on the cover for the lights.