Assuming you have two coax cables
First look round the back of the box. Check the two cables are connected to the two outer connectors with the centre one not used.
If incorrect put right (turn the box off before changing connections) and do a factory reset. You should see a message during the reset that two cables were found.
If the cables were correct then
Menu System Diagnostics and post signal strength and quality for both tuners.
Now Open the setup menu with Freesat Tune highlighted
Without looking at the screen press the following in succession on the remote
Red Green Yellow Blue Green Yellow Blue
You should get a Menu – Manual Setup
Press OK on Antenna Setting
Post what Antenna Type and Connection Type is shown