Serpentine assembly question

The car is an 87 Cadillac Fleetwood d'Elegance, 4.1 engine. The serpentine tensioner assembly was taken off, and I see how it is supposed to go in, but I don't know how to get the two pegs lined up and keep the pulley in it's designated position, the tension is fightin left and right on there. Any advice or instructions on how to put it back in place would be appreciated.