PBoTG

How do I get an item collector to show an interaction UI? I tried adding a scene object (i.e Enter, Open), but that didn't work.

gamingislove

Scene objects are used to add content information to it (e.g. to display it's name, etc.).

Otherwise, item collectors should display an Interaction type HUD when they're available for interaction. If you want a different HUD for item collectors, you can set up which interaction displays a HUD in the interaction HUD's Interaction Settings, e.g. disable Any Interaction and enable Item Collection to only show the HUD for item collectors.