REV Control Hub Guide:

https://docs.revrobotics.com/rev-control-system/control-system-overview/control-hub-basics

     Control Hub: Getting Started using a Web Browser:

     Connect a Driver Station to a Control Hub:

     Driver Hub Getting Started:

    Connecting a Driver Hub to a Control Hub:

     REV Expansion Hub Guide:

https://docs.revrobotics.com/rev-control-system/control-system-overview/expansion-hub-basics

     Connecting a second Expansion Hub

     REV Driver Hub Guide:

https://docs.revrobotics.com/rev-control-system/control-system-overview/driver-hub-specifications     

     REV Electronics Tutorial Playlist:

     FTC Robot Control System Programming for Beginners:

     Game Manual 0 Electronics Overview: 

https://gm0.org/en/latest/docs/power-and-electronics/index.html