how do I access the set up screen?

Re. Thomson DT16300 Top Up TV+Digital TV Recorder
I have been unable to access the set up screen. I've tried presing the AV button on my TV which provides 3 options, analogue TV programs, S-VHS, and what should be AV1 accoring to the manual, however this last option brings up on screen an arrow entering a square and not "AV1" - I suspect this is the option that should be selected but still no set up screen appears when I turn on the recorder. All I get instead is the no signal icon. Please does anyone know what I need to do to set up this recorder to search for channels?