NDI® source devices such as OMNIBUS NDI® Transmitters or MINIBUS Transmitter instances will appear in the MINIBUS Receiver as long as you are connected to the same network as the transmitters, please ensure all devices are connected to the same WiFi network.
If yo have a firewall enabled on your machine you may need to whitelist NDI® Protocol. Please refer to NDI®'s help page.
You may also need to allow up to 10 seconds for the plugin to scan your network and display available NDI® transmitter sources.