Connection between the motors of the Linear Actuator, Tic T825, and Arduino Uno?

Hello, I’m trying to connect a micro stepper linear actuator to a Tic T825 that will be connected to a Arduino Uno. The Tic T825 incorporates a DRV8825 driver on it. The Tic will be connected to the Arduino via serial control (RX, TX pins) and linear actuator will be connected to the Tic (A1, A2, B2, B1). I'm wondering how will the motors correspond to the Arduino if I'm only using 2 digital output pins (10,11) for the serial control? Like which pin on the Arduino corresponds to the motors?