Hearing aids can be connected to radio aids either through direct input leads, and connecting shoes, through connecting shoes which directly attach the receivers, via a neck loop or bluetooth streamer.
Hearing aids will either automatically connect to the radio aid, or need to be set up by an audiologist. There may be a specific programme which is used for the radio aid. To connect via a loop, the hearing aid needs to have a T or induction loop enabled.
The manuals that come with the systems explain how to use them.