I think the example shown in the circuit diagram "external controls using optocouplers" would be the most suitable when using a stepper motor controller board with step and direction outputs. You will need some more circuitry (quite simple) to control both direction inputs with just one output, a simple inverter which can drive the optocoupler in one of the direction lines will do. - Anyhow, the circuitry you are going to use is a very basic one, and the stepper motor will operate in full step mode only. This usually yields a "harsh" and probably "rattling" behaviour of the stepper motor. Also, the resolution of the motor movement is restricted to its full step angle (if you have a motor with 100 steps per rev. or 3.6 deg per steps, it is NOT possible to drive the motor to postions off the 3.6 deg grid). Also, there is no feature for controlling the motor current, so you are restricted to motors with at least 0.6A current handling per coil, if you use "weaker" motors they probably will burn. From my experience, you may use motors with 2x up to 4x of the driver's current rating (i.e. 1.2A to 2.4A), they usually will run properly if you do not exceed the maximum mechanical load.
