I always start on the crank pulley. Just wrap around there with the belt pointing toward the a.c compressor. The bottom edge should go to the compressor and the top to the tensioner. And so on from there.
The service CD has the diagram in it as well.
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM