Disclaimer: I have not used this feature. However, I believe what you are referring to is also provided in my 2020 Cougar 1/2 ton.
In order for you to connect to the Furrion antenna, you will need to purchase the
Furrion router/wifi extender. What is mounted on the wall in your trailer now is simply a cover plate. Remove it and you will expose the connection point for the router.
Furrion provides data plans you can purchase. However, I've read that many people simply purchase the router, and use it for its wifi extending capabilities by connecting their cell phone's hotspot to it. You can Google the data plans...they seem pretty pricey to me.
Be curious to know if this method of connection (to your phone's hotspot) also
boosts the signal, in addition to extending it. Something that would elevate my hotspot cell signal a bar or two would be pretty OK.