Yes, that's it. Stepper drivers have come down to a pretty simple interface but there are a few gotachas you should know about.
All of Makerbot stepper drivers and even aftermarket Pololu or easy drivers have pull up resistors built in on the step, dir, and enable pins, so in order to go active-they are pulled low to ground. So in your code, you will need to ensure the output pins of the arduino are set active low when defining the digital outs. This is contrary to what most people think as active high would be +5 volts.
You'll see there is nothing special-just look at the schematics for either the gen3 for gen 4 motherboards.
Enable energizes the coils based on the state table in the driver. (thus locking the motor at that position)- you need enable active all the time you want to move or stand locked still.
Dir- just determines which way the driver is going to go in its state table
step-actually cause the state table to jump to the next state (depending on direction pin)
FYI reset is broken out on the stepper driver but we have no reason to use it. It just starts the state table at it's first position, but that never matters in any application I have seen to date.
http://www.thingiverse.com/derivative:6945
