DFRobot Tank Devastator servo control on Adafruit servo HAT

I am installing the devastator servo motors to the Adafruit 16 channel servo HAT for Raspberry Pi 3B+. I am able to run the DF9GMS off this same board but the same pwm commands do nothing for the tank motors. When I plug the tank motor into the pins, the motor starts turning slowly but no commands stop it or change it. The page below says it works with Raspberry Pi 3B+ but it doesn't say how. Because the Adafruit servo HAT runs other servo motors, I assumed this would work, like the DF9GMS motor does. Please let me know where to find the solution to this problem.

https://www.dfrobot.com/product-1477.html