Hello Paynethorl,
Are you trying to access that setting in photo mode or video mode? That remote is compatible with the camera in Photo mode only. In photo mode, you would find that option in the purple antenna menu #1. Select [Wi-Fi/Bluetooth connection]. Then select the [Connect to Wireless Remote] option on the next screen. The EOS R5 C is essentially a cinema camera with you put it in Video mode. That wireless remote is not going to work. The video side has a feature called Browser Remote that would allow you to control the camera remotely from a web browser of a connected device. You would need to connect the WFT-R10 Wireless File Transmitter to the camera however to use these network functions in video mode.
