When you create a new Local Area Network (LAN) chat, Underpass will automatically listen for a connection. The name of your computer on the network is listed in the settings. Another device can find your Mac on the network via your computer name. See Basic concepts for more details on network discovery.
If another device on the network is already listening for a connection, and you want to start a chat immediately, you need to select the other device by its computer name.
Once you've selected the device, you can start a chat from the toolbar or from the main menu.
Regardless of which device started the chat, you can stop the chat immediately on your Mac from the toolbar or from the main menu.
The popup selection in the settings will be remembered, so after you stop the chat you'll be able to start again easily without having to select the computer name every time.
If you want either device to be able to start a chat, then each device should select the other device's computer name. For example with two Macs:
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