You also have to have found the menu item that says source (source of the input you are looking for)
So, lets assume you have it set to antenna, and the booster button is on... then try a scan and see if it brings in channels assuming your antenna is up and there is channels there.
OK.. it worked. So now you change the source to cable, and plug in to the shore cable.. you should not have to scan for that, they should just be there.
But they are not.. so.. take a longer wire from their cable outlet through a window to your TV and see if you can get it to work. That might prove your cable system isn't working. So then you have the connection from your outside connection to the antenna booster... and the connection from the booster to your TV. again, you can check the latter by putting in your wire and seeing it that makes a difference.
It's never easy.. but just working through all the parts and figuring out what is not working is the key.
I eventually found my problem was my internal wire from the outside to the booster had the center wire cut just 1/32 of an inch too short where it screwed into the booster, and I saw it was not as long as the other wires with the center pin... and I pulled it out with my needle nose pliers and presto, cable connection was perfect.
Mike
2012 Winnebago Impulse Silver 26QP
2005 16.6 Double Eagle
2018 Jeep Wrangler JK
previously Snowbird Campers,
Triple E Motorhome and Fifth Wheel