Enforce username matching from In-game to your discord server.

So if understood right that's exactly what i need. For example player steam name is RustyPlayer123 and inside the server i see him like this. Then he joins in the discord server with his account thats named ASD123 and how i am supposed to know who's this. Tried with myself. Steam name Flammable, changed discord nickname to NONAME and waited but bot didn't renamed myself. Any ideas if should work this way as i understood why its not working then. I have Admin and at all Owner rights in my discord server and bot have 1 role with ALL available permissions ON. So?