Van will not start the belts turn about 1 inch?

Charge the battery at a slow rate for an hour, then try to crank the engine. 12.2 volts means the battery is good but discharged. You're pretty close to that. A fully-charged battery will be 12.6 volts. If that doesn't help, measure the voltage right on the battery posts while a helper tries to crank the engine. Next, move the voltmeter probes to the cable clamps and measure again. Tell me what those two readings are. Also remove the drive belt to see if it starts you may have a locked up accessory.

And what happened?

If the starter still cranks slowly or not at all, measure the voltage on the stud on the starter solenoid that the battery cable is attached to, then have a helper crank the engine. To be most accurate, place the other meter probe right on a paint-free surface on the engine block. As long as the voltage there, during cranking, is 9.6 volts or higher, that should be enough for the starter to work properly.

That suggests a bad starter. To know for sure really requires a professional load tester so you can measure current flow. Instead, one thing you might want to try first is removing the spark plugs, then see how the engine cranks.