The busboard is connected to your power supply and can power up to 20 modules in your system!
See https://polykit.rocks/busboard for technical details and assembly.
Disclaimer: Kits or PCBs like this require a certain experience to assemble. A set of tools and basic understanding of electronics and components are required. Please take great care while assembling it. All kits/PCBs are sold at the purchasers risk. Used or assembled kits can't be returned.