Its not hard, but it is time consuming the first few times. You need to accurately establish true TDC (most people don't trust the pin) and then make a pointer of some kind and mark the damper at the pointer so you can find true TDC reliably while using the timing tool and barring the engine over.
The instructions on the dodgeram.org site are pretty good. But there are tricks and tips you learn after doing it several times.
One of the most important is to make sure you thoroughly clean the pump shaft and gear after you pop it loose and before you set the timing.
-Jay