Lynxmotion Aluminum A4WD1 MTS 12T Rover Kit what electronics to buy

My college robotics team is trying to build a small robot using this kit. We are purchasing this kit, but need to know what other products to buy with it. We have purchased a Raspberry Pi microcontroller and are purchasing a motor controller hat compatible with the Pi to control it. In addition, we are purchasing a 12 V battery and a 5 v battery for the Pi. We also need a conversion/wiring harness (can anyone point me to one?). We are also purchasing motor controller hats compatible with the PI (link here ). It can power 2 motors, so will we need 2 to power all 4 motors on the tracking system?

What kind of harness would be that ? (from what to what)

Regarding the motor controller, you only need two outputs as far as they can handle the current of the two motors. (10A should be fine)
Since in a Tracked vehicle motors on each sides are in parallel.