Pretty self explanatory really, mounts the Printrboard 3D printer controller in the back right corner of your printer with the comms cable oriented to go straight out the back and with the SD card port and rest button on the top where you can get to them easily. Also features plenty of cable tie holes all around the board to help tidy up your wiring (I'll post another photo of mine wired up when I get on to that).
Lines up with the two side rails and mounts using standard T-nuts and M5 machine screws.
Print it out and clear out all the holes.
Printrboard mounting holes are 3mm, use M3 macing screws and have captive nuts.
Cable tie holes are all 4mm.
The four mounting holes are 5mm.