How to connect this motor driver board to Arduino to drive bidirectional motor? I am familiar with using PWM on Arduino and have done so with simple 3-pin interfaces: e.g. PWM, DIR (direction) and GND pins. Choose a direction with DIR, set speed with PWM in software (0 - 255), simple stuff. 

But this board I'm buying seems different:

http://www.ebay.com/itm/DC-43A-Double-BTS7960B-Stepper-Motor-Driver-H-Bridge-PWM-for-Arduino-Smart-Car-/141485439094

There seems to be 6 control pins:

R_IS, R_EN, RPWM, L_IS, L_EN, LPWM

But from what I understand this board would only be used for controlling one motor bidirectionally, so why is there a distinction between left and right? 

So how would I go about using this motor driver board in a similar way to my PWM, DIR, GND boards that I've used before to control the motor direction and speed? 

Thanks!
I guess you have used DC Motor for your earlier cases? Or Step Motor with a logic on the stepper controllers?

Here you have two H Bridges which drives one Step Motor. So as I understand it, you have two PWM Inputs, one for each output channel to the coil windings of the stepper motor. Like an encoder signal you can set the direction with setting one pwm before the other. So the step motor is controlled via unipolar stepping.

For further help you need to say which motor you want to use with this card. But first I would look at the different stepping modes (unipolar and the two bipolar and maybe microstepping).

Greets