So, it the motor going at all?
Is it going sometimes but not other times?
Is it going, but not at the rate you want?
Is it going at the rate you want, but sometimes its uneven?
Can you get the motor going ok by itself, but when you attempt to integrate this with your other code it doesn't quite work right?
Can you attach some LEDs to your output pins, and verify that the correct sequence of pulses is being sent?
Can you get serial output from the arduino at all? What does your debugging code say?
As for just diving in: I attended an "introduction to arduino" night at "Make Hack Void", a local maker group. It was very helpful at getting started.
Have you tried the sample sketches? Can you at least get an LED flashing - do something completely unrelated to your motor? Does your conveyor belt sketch compile at all?
What I'm saying is that there are multiple points of failure from point A (buying a load of gear) to point B (getting your conveyor belt running), and to get advice you really need to be more specific about where along that track things are not working for you.