From the product web page:
In a typical application, the power connections are made on one end of the board, and the control connections are made on the other end. The enable (EN) pins do not have pull-up resistors, so you must pull them to +5 V in order to wake their chips from sleep mode. The fault-status (FS, active low) output pins may be left disconnected if you do not want to monitor the fault conditions of the motor drivers; if you do connect them you must use an external pull-up resistor to pull the lines high. IN1 and IN2 control the direction of their associated motor, and D2 can be PWMed to control the motor's speed. D2 is the “not disabled” line: it disables its motor driver when it is driven low and enables its motor driver when driven high. Whenever D1 or D2 disable a motor driver, that driver's FS pin will be driven low. Each feedback (FB) pin outputs a voltage proportional to the H-Bridge high-side current of its associated driver, providing approximately 0.59 volts per amp of output current.
You will want two digital lines to control the direction of your motor, connected to IN1 and IN2, and you will want one PWM line to control the speed of your motor (connected to D2).
For the most part, this driver is designed to be a carrier board for the MC33887 IC, so you should really read the MC33887 datasheet if you want a better picture of how it works.