The centre groove of the crank pulley (currently empty) should have the alternator belt in it.
You'll need to slacken the alternator adjuster and its mounting bolts slightly, likewise with the A/C compressor adjuster and mounting bolts, remove the A/C belt and the alternator belt, refit the alternator belt between the crank pulley and alternator, tighten the adjuster until the belt is tight then re-tighten the alternator mounting bolts.
Do likewise with the A/C belt and the adjuster and compressor mounting bolts.
Now you've had some practice and encountered at least two of Volvos unusual adjusters, slacken the PAS pump mounting bolts and adjuster locknut then tighten the adjuster on the PAS until the belt is tight. Now tighten the PAS pump mounting bolts again.
You will find there is usually one mounting bolt with each item that allows the unit to move with the adjuster to tighten the belt. It's a few years since i had a red block so i can't remember exactly how they go and they're different on what i have now.
You'll need a good set of metric spanners, socket set, penetrating oil and patience - oh yeah and a methodical approach. A torch might also be usefuil and a small mirror to help you see what you need to undo/do up.
