Next, attach the LMI Sunray Bracket to these mounting holes by passing the two 1/4-20 threaded holes through the slots in the tray, and tighten them.

Those two Nylon screws are one way of securing the pods to the bracket, but they aren't my favorite way. If you want to use the nylon screws to secure the the pods, thighten them all the way down, install the pods, and back them off with a narrow screwdriver until they "lock" the pods in place.
My favorite way is to use pod lockers, as shown below.

Slide the pods into place, place the pod locker in the center of the bracket, and tighten down the allen headed set screw to "lock" the pod in place.
