Got a purty new Mk5 and relay board but don't know where/how to attach the relay board? This design makes use of two existing holes under the motherboard. I used T10x16mm screws since I had them lying around. Use wood screws, sheet metal screws, whatever. Put two screws through the holes from the inside of the Makerbot to mount the Standoff. Use four screws (or only two if you are feeling lucky) to attach the relay board to the Standoff.
Even though I have a heated build platform, I was having trouble getting the first layer to stick on blue painters tape so I gave up and used a raft. The gcode file reflects that. Printed with Mk5, still tweaking settings, currently 220*C, 0.42mm layer thickness, 40 mm/s feedrate. 36 minute total print time.