Hi Sarah - welcome to the forums
There are no timing marks on the 16V engines - all the alignment is done with two setting tools. A 'U'-shaped plate fits in the slots at the non-pulley end of the camshafts, and a locking pin screws into the crankcase.
Be very careful, and read up about what is involved - many have come unstuck on this engine!
Just out of curiosity, is the cambelt change a scheduled one - or possibly because of an uncertain previous history?