Are you looking for more detail on how/where to run the coax wire? Or how/where to mount the omni antenna?
BTW, I'm assuming you have the equivalent to their trucker antenna? As that unit doesn't need a steel ground plane.
Many have improvised with telescoping pole: either swimming pool, painter pole, irrigation; and just strapped these to the awning supports once at site.
That's going to depend your FC 28. Does it have a fridge flue?
It may be different, but food for thought on how I did mine, albeit with the complexity of a directional yagi external antenna