See video: https://www.youtube.com/watch?v=Q-kdP2roqwU
You will need to download the digitalWriteFast for Arduino: https://github.com/NicksonYap/digitalWriteFast (may also be available thru Arduino libraries manager)
Open Arduino_Lego_Tank.ino program with Arduino
Open the Processing_Tank_GUI.pde file with Processing (https://processing.org/)
Eagle schematic with PDF copy included as well