You navigate through it just like the other two panels.
Unlike the other two panels though, the comms panel has a sneaky third options in the menu, which might be what's wrong with yours.
If you are using your head to activate the panels instead of using the UI focus or POV hat/buttons (which is how you do it by default in non-VR mode), you can change how the panels behave when you look their way.
It's under "Mode Switches" in the options.
One option is "Do nothing" - i.e. the panel doesn't open when you look at it and you have to activate it manually. That's what I use because I don't like random panels popping up in the cockpit as I'm looking around.
The other option is "Focus the panel" - that one opens the panel when you look at it and you can do stuff in it as per usual.
The comms panel has a third option that only SHOWS the panel when you look at it but doesn't focus it. So you can't do stuff in it unless you properly activate it by a UI focus switch or a dedicate button, but you can still check incoming messages etc.
It's kind of handy, to be fair, but I think that's your problem. Switch it to "focus the panel" and it should function normally when you look at it.