Repository with SiPM PCBs and Instructions
CHOOSING PARTS
Eagle (and generally all schematic/pcb softwares) come with built-in libraries containing some widely-used parts. Most non-specific parts can be found here, so it is useful to check these before either downloading external Eagle libraries from some external internet source or creating your own (which is possible, but painful).
CREATING THE SCHEMATIC
CONVERTING SCHEMATIC TO PCB
SENDING THE PCB TO PRINT