A VCR records from its own internal (analogue) tuner, which takes its signal from a conventional aerial (where analogue TV is still switched on). It doesn't contain a Freesat (or Freeview) tuner, so it can't record directly from a digital source.
The only way that you can use a VCR to record from a Freesat (or Freeview) set-top box is by connecting the 'AV' output from that box to the 'AV' input of the VCR, using a Scart lead (or, sometimes, by using phono leads).
Since there is only one digital tuner involved, you can't record one channel while watching another; you can only record the output of the Freesat box (while, if you so choose, watching it on your TV at the same time). Channel selection for the recording is therefore made by selecting the appropriate channel on the Freesat box, with the VCR being set to record from 'AV' (or 'AV1' or 'AV2' or 'Ext' or 'Aux' or 'Line' or 'Line In', depending upon the model!) rather than from any numbered channel.
Since your Freesat box has only one Scart output, the simplest way to sort things out would be to split the signal into two, using a Scart splitter:
http://www.google.co....20BQ&ved=0CLEBEPMCMAk
(Widely available in 'pound shops', etc).
Feed one output (from your Freesat box) to the TV, with the other going to the VCR. Then you can record as above. However you'll need to swap some cables (or employ another Scart splitter or switch box) in order to watch the recording.
While I love my old VCR (as it allows me to play all of the cheap VHS videos I buy in charity shops), VCRs aren't really suitable for use with digital TV because, as stated above, they don't have the right type of tuner inside them. You ought to consider getting a Freesat PVR.
Chris