Buy a Haynes or Chilton repair manual from a parts store.
belt diagram for a 1996 Geo Prizm
This might be helpfful. How do you Change a fan belt on 94 prizm?
how do you wrap the serpentine belts around on the 1999 geo metro
where is the vacuum diagram located on 1995 geo prizm
1994 Geo Prizm has a timing belt.
How do you replace the timing belt on a 1994 Geo Prizm 1.6?
A 1995 Geo Prism may experience squealing if the power steering pump is failing or the serpentine belt is loose. Tightening the belt and applying a belt conditioner are the first step to addressing this problem.
You can get a fuse box diagram for a 1990 Geo Prizm at your local auto parts store or at the library. Another way to get one, is to contact a local Geo dealer.
It is squealing because it is loose or worn out. Tighten it and if that does not help, replace it. If it is a serpentine belt, just replace it and check to make sure the idler tensioner is working properly.
Loosen the belt tensioner and take the old belt off. Put the new one on and let the tensioner back in position. If you don't have a tensioner, you'll have to loosen the alternator and ac compressor adjusting bolts.
Most likely a belt is slipping.
This was for a 1994 but try searching here. How do you Change a fan belt on 94 prizm?