The mod is to remove the springy leaves at the bottom of the stem part, there's a thread on DT and I think litster did a thread here.
As to assembly... PCB or plate?
Drop the stem in through the bottom of the bracket part, it is orientation specific but just looking should be enough to figure it out. From the front carefully insert the wire end into the stem then seat it into the hinge clip. Repeat on the other end with proper orientation. Then either mount it to the PCB, or carefully place the stabilizer clips diagonally onto the plate, wire-side first. Make certain that spot is well seated onto the plate before tilting the other side down and getting the whole thing seated. It's tricky with the plates I've worked with (phantom alu and steel). You have to know that it really does fit with extremely little damage to the plastic and do your best to get it in that way.
