The complete step-by-step assembly guide can be found here
JuiceBus is the next step for power-distribution in eurorack systems. Its ultra-narrow and adjustable design makes it great for both small and big systems. It lets you connect up to 20 modules with dedicated pin connectors. Optionally it can convert your standard +-12V to +5V and therefore feed your digital modules with power. This feature can be easily bypassed with a dedicated jumper in case your powersupply provides +5V already. You can use it either as a long busboard with 20 connectors, or you can simply split it at its breakpoints and have one main powered busboard of 11 connectors and secondary busboard of 9 connectors for smaller eurorack cases. In this scenario you just connect the two pieces with faston connectors or simply use one ribbon powercable to connect the powerpins.