Cam timing a 20V

Hi All, I am new to the group, and I need some advice with a 1993 Audi coupe 20V, timing belt broke and bent most of the valves, my friend removed both cams and replaced the valves, but he can't find any info regarding timing both cams together with the chain, and there doesn't appear to be any marks on the chain sprockets, Would any one in the group have a repair manual with this info, TIA Peter