Volvo Repair: Belt Changing, slide bolt, alternator

Question
I have a 87 GL.  Two belts need replacing.  I've purchased the new belts...how do loosen things up so I can install the new ones?

I loosened the bolt on the front of the alternator but it didn't seem to help.
Thanks.

Answer
you need to loosen the 13mm nut on the front then loosen the 10mm slide bolt at the end of the adjuster.this will loosen the alternator.same goes for the power steering.for the A/C there are 2 13mm nuts and only one slide bolt near the front of the compressor.