remove engine fan timing cover and whatever else is in the way, then the drive belt, and crank pulley,
remove the timing belt crank pulley cover, then release the bolts on the tensioner, you can now turn the cam gear approx one tooth anti clockwise, then slide the belt off.
to put it on, turn the cam pulley one tooth(ish) backwards again, and let it spring itself back to TDC properly, putting tension on that half of the timing belt, dont let go of the spanner that should be on the crank pulley either, then force the belt over the tensioner.
THE ONLY REAL MAIN RULE IS, TURN THE ENGINE OVER ATLEAST TWICE, BY HAND. TO DOUBLE CHECK THE TIMING didn't JUMP A TOOTH WHEN PUTTING ITSELF UNDER TENSION BEFORE CRANKING OVER WITH THE STARTER.
good luck!