The ActivityBot connections to the Arlo’s DHB-10 motor control board use the same servo ports as the ones you used for your ActivityBot’s servos. The encoders are connected to the DHB-10 board, so you won’t need to connect encoders to the P14 and P15 ports, so they’ll be available for connecting to other devices.
NOTE: The 20k resistors are not needed when connecting your Activity Board to the Arlo. You should not have resistors in P14/P15; if they are in your breadboard, remove them and continue with this tutorial.