in that video is the white Sphere your Destructible Blueprint? If you just want it to get destroyed when you walk into it theres a setting in the destructible editor that says “Enable Impact Damage” if you check that on it should fracture when you walk into it. Otherwise youre character will just keep bumping into it and youll have to do it through blueprints by using the apply damage node (which can get a little more complicated).
if the other sphere was your destructible, then double check that your pawns collision settings are set to block destructibles rather than overlap or ignore.