What do they mean by rotating the engine by hand?

Do you mean there is no engine rotation when trying to start it or do you mean that it's cranking but no start condition you know none of us are there with you obviously so very vague questions don't help the situation try to rotate engine by hand if it's free and rotates now check all electrical connections clean fuses and relay blades no year given no engine given my crystal balls in the shop and my genies on vacation in France so the case of wine I wished for won't be here for 2 weeks to help me deal with posts without proper information about vehicle/symptoms it's your job to tell us precise information so we can get you to the problem cause look how much typing is already involved here there's a lot of different things for different vehicles

Your car has an interference engine, which means if the timing belt is broken, the pistons will strike the valves. If your engine turns over and there is no noise of internal metal-to-metal contact, your timing belt is not broken. If your engine does not turn over, and you suspect the timing belt may be broken, remove the valve cover and SLOWLY rotate the crankshaft a few degrees by hand, watching if the camshaft rotates. If the camshaft rotates, the timing belt is not broken.
You provided no information on why you think the timing belt may be broken, although you refer to having good electrical power. Does the starter engage? If not, it has nothing to do with the timing belt. Does the starter engage but the engine doesn't start? If so, timing is way down on the list of things to check. After checking spark, fuel delivery, compression, etc.

That hard stop is the valves hitting the head of the piston, you most likely have bent a valve, you have the valve timing wrong.

IF BY DIAGRAMMS U MEAN THIS THEN LET ME KNOW

You mean standard or reverse thread?
Usually crank nuts are reverse thread in relation to the direction of the pulley.

So if the pulley\engine spins clockwise then the nut is probably going to loosen by spinning it counterclockwise.

Afterall it would do no good to go down the road and have the rotation of the engine spin the nut off of the crank pulley eh?

Clicking instead of starting? The clicking is usually the starter solenoid being pushed out to the flywheel. If your engine isn't turning then it means that either your battery is too weak to turn the engine or your starter has malfunctioned or maybe engine that your engine has locked up.

Recommend you either jump start the car or use a battery charger with the start function to see if it is the battery or starter/engine lock up. If the engine still does not turn over. Take off your serpetine belt and try to rotate your engine with a large socket. If the engine rotated, then it is most likely your starter/solenoid that is bad. If the engine would not rotate by hand then something inside the engine has malfunctioned and it will take some serious work to get it operational again.

You'll need a Serpentine Belt Tool and a socket set.

Rotate the Caravan's serpentine belt tensioner assembly clockwise to relieve the tension on the belt. Slip the belt off the tensioner with your free hand before rotating the tensioner back to its home position. Remove the tool.
Extract the two mounting bolts that hold the serpentine belt tensioner assembly to the Caravan's front engine cover using your socket set. Depending on your physical size and dexterity, you may find this easier to accomplish through the top of the engine well or through the passenger-side wheel well.
Pull the old serpentine belt tensioner assembly out of the Caravan's engine bay by hand. Place the new serpentine belt tensioner assembly on the Caravan's front engine cover and bolt it in using your socket set.
Rotate the new serpentine belt tensioner assembly clockwise with the serpentine belt tool and then place the belt on the pulley by hand. Rotate the new serpentine belt tensioner assembly back into place. Remove the tool and close the hood.

Remove the spark plugs. Block the number 1 cylinder hole with your hand(LHside of engine) . Rotate the engine by hand/wrench. As soon as you feel air coming out of the hole rotate the engine until you feel it to start sucking on your hand. Look at the position of the rotor(remove the distributor cap). This is the number 1 plug lead position. Moving clock wise connect cylinders 1-3-4-2 in that order.

complete procedures are posted at AutoZone.com: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c152802619fd

Do you mean timing belt ot serpentine (accessory) belt?
Belt diagrams are below:


Fig. Belt routings on the 1FZ-FE engine



Fig. Belt routings on the 3RZ-FE engine



Fig. Belt routings on the 5VZ-FE engine
2UZ-FE Engine
To remove the serpentine belt on the 2UZ-FE engine, position a suitable sized wrench or ratchet and socket over the belt tensioner bolt, rotate the tensioner counterclockwise to release the belt tension, then remove the belt. The pulley bolt for the tensioner has a left-hand thread.
When installing the belt, make sure it fits properly in the ribbed grooves and check to be sure the belt has NOT slipped out of the groove on the bottom of the pulley.



Fig. On the 2UZ-FE engine, rotate the belt tensioner counterclockwise to release the belt tension

Remove the serpentine belt and try to rotate the engine by hand. Take the spark plugs out and try to rotate the engine by hand. If it has an automatic tranmission disconnect the flexplate bolts and try to rotate the engine by hand. If no no luck the engine is seized somewhere and will need replaced or overhauled.