Flywheel is incased in gearbox nowhere near cam belt.
It doesnt sound like you have a clue so i would leave it alone if i was you. But then again its only an old laguna worth about £300 with an MOT so wont be too much bother if you break it.
Cut off old belt with knife/scissors, fit new belt to bottom of pulleys and use a lever bar to stretch the belt on top pulley, before this undo little pulley so loose or take off completely then put back on again after using the lever bar to lever it on. Its well easy, even a girl can do it :-)
stupid stuart, November 2008