Fixing my belt routing
Im not sure what year engine/body style you are working on - but the set up you are trying to use looks like a 72/73 vintage set of pulleys. The problems with getting this junk to line up is if you are using a mis-matched set of parts or brackets. Having said this - You should run two belts on this kind of set up. One belt goes around the fan crank and alternator. The other belt is short and runs from the crank to the power steering pump. If your brackets dont line up then you need to adjust the spacers used on the alternator bracket and or power steering pump. If you are in a rush buy a bunch of 3/8 flat washers, (I like to use 5/16" cause they fit tighter) and mock it up. You can then adjust by removing or adding washers to get close enough for it to run. Later you can get some 1/4 " steel (NPT) schedule 40 and cut spacers to match your washer set up and replace them. This can be a frustrating experience, but with some patience it will end up being okay and work fine.
Good luck with it.