Controlling multiple VESC over SPI

Hi,

I am using the VESC 4.12 hardware for a project. For the project I am using 4 VESCs and all of them receive their commands from one central computer/controller. I am not using CAN because of the data rate I require and the speed of my control loop. 

I am trying to control it with SPI. On the 4.12 schematic (BLDC 4), the comms header (P3) has SPI pins available. What do I need to do to control the VESCs over SPI. Can you tell me how to go about this, and can you confirm if the SPI logic level is 3.3V or 5V?

Thanks