F1 key, should hold a keyboard commands listing of what key, does what... & should... include a mapping of what key has been assigned to radio/gramophone activation, as well... I say, should... if the mod maker included that (updated) in the mod.
I find that most follow the path of that last command function, there is the commands bar at the bottom of the screen... that 1 off to the far right... maybe the 1 just before the last one... I think.
Crackalacking that 1 open, should pop up a sub-menu that will show a... radio or gramophone icon & clicking on that will pull it up... sometimes attached to a map showing shipping, aircraft patrols, info... usually, or just a textured image of a radio or record player... if it's not merged with that map I mentioned.
Hopefully, I haven't lost you there... or left you confluzzled... by now...
& this helps...
M. M.