You will need to connect the recorder via scart, usually one scart is marked to TV the other to a recorder. Generally if the scart to the recorder is used the signal to the TV can be taken from the recorder thereby freeing up a scart from the Sky box.
Otherwise turn on the recorder and make sure it is set to receive from the AV input you have chosen on it. Go to the Sky planner from tv guide, highlight the recorded program you wish to cvopy and press the red key (copy) then press select.
Press record on your recorder and play on the sky box. Do nothing until the copy is complete, you cannot view anything else during copy. You do not need to watch the recording before you copy it.