You've checked the servo motor controller and the servos; you'll now connect the motor controller to the Raspberry Pi Zero and make sure you can control the servos from it. Remove the USB cable from the PC and connect it to the Raspberry Pi Zero.
Let's now focus on the motor controller by downloading the Linux code from Pololu at www.pololu.com/docs/0J40/3.b. Perhaps the best way is to log into your Raspberry Pi Zero through PuTTY, then type
wget http://www.pololu.com/file/download/maestro-linux-100507.tar.gz?file_id=0J315. Then, move the file using
mv maestro-linux-100507.tar.gz\?file_id\=0J315 maestro-linux-100507.tar.gz. Unpack the file by typing
tar –xzfv maestro-linux-100507.tar.gz