You can record the channel you are watching with just the one input.
Turn the power off at the wall - and connect the cable to lnb1 on back of the box.
Turn the box back on.
You then got to settings, press 0 (zero) then 1 then select - you then get into the hidden menu and from there you select Single feed mode. Turn it on.
You can't record say BBC1 and watch BBC2 at the same time. - for that you would need a second cable from your dish. If you do that, you may need an new lnb - thats the bit the cables come out of - as yours might only have one output.