Before connecting to a Channel using the just:in user interface it is mandatory that the Channel is configured and running in just:in Engine. Refer to the chapter just:in Engine if you have not yet configured the Channel(s) yet.
Connecting to a Channel
Optional: if there are multiple Viewers, first select the Viewer you want to connect to the Channel. You can still reorder Viewers later by drag & drop.
Go to the menu command Channel → Connect or use the shortcut command + K.
Enter the IP Address and the Port of the Channel.
Press the Connect button. The Channel Preview should now be shown.
If you should get this warning, double check your IP-Address and Port as well as the configuration of just:in Engine and the network.
Disconnecting from a Channel
Optional: if there are multiple Viewers, first select the Viewer you want to disconnect from.
Select the menu command Channel → Disconnect or use the shortcut command + shift + D