The front shock cord passes though the main sheet block and around the spar. The Rear goes around the hiking strap and then round the spar. There should be a diagram that comes with the set.
Thanks for that because I had no idea where two extra shock-cords went or what they was for, all I got was the paper that showed how to rig the shock cord on to the lazy bones itself but no mention that they could be attached to the boat, nice one thanks.