Hi,
It looks like I'm going to have to redo that document as the primary and backup copies that I have are both corrupted.
The Add button is found on the Transmitted Channels tab.

- Add Button.PNG (13.18 KiB) Viewed 9706 times
And the Select (or change if an existing channel is in place) is in the Add Comms Channel popup window.

- Select button.PNG (16.64 KiB) Viewed 9706 times