BY memory, there is a bolt that snugs the alternator, then there is the adjusting nut. Below I copied and pasted the instructions for replacing the bushings, but you can adjust to use it to tighten belt also:

I hope this helps!


Alternator Mounting Bushings. [Editor] Over time, the three rubber bushings securing your alternator in its engine bracket can compress, allowing the pulley to become misaligned with the crank pulley and accelerating belt noise and wear. You can replace these with OEM rubber bushings or aftermarket polyurethane, which are more robust and do not compress as easily. The latter may be had from IPD. To replace your bushings:
Disconnect battery negative terminal
Use penetrant oil to loosen the tension adjusting, securing, and bracket nuts but don't soak the belt
Unscrew the 10mm tensioner adjusting bolt beneath the side of the alternator by about 1.5 cm. Remove the belt from the pulley.
Loosen the 12mm bottom securing nut and remove it from the adjusting assembly
Loosen the top long bolt and nut (12 & 13mm) supporting the alternator in its bracket
Remove the bottom nut and bolt (12 & 13mm) holding the alternator to the bracket
Swing the alternator up. Using a screwdriver, push out the old bottom bushing and replace it
Swing the alternator back down and replace the bottom bracket bolt and nut
Remove the top long bolt and nut and swing the alternator back to replace the two top bushings
Replace the top bolt and nut and the securing nut
Tighten the bracket nuts (not the securing nut!) and retension the alternator belt so you can press it down about 1/4 inch under moderate finger pressure
Once you tension it, tighten the securing nut firmly and then back off the adjusting bolt so it bears no tension from the belt
Reconnect the battery negative terminal