Mine are pretty straight forward. In the picture below I still have the end caps off the cabinet. I used a 1x3 cleat screwed directly to the ceiling with TEK screws, then used an air stapler with 2" finish nail/staple to attach the oak frame to the 1x3 strip. For additional support, I also drilled some pilot holes through the oak inside the door opening upward to the ceiling, then installed some 3" TEK screws that helped 'pull' the cabinet tight against the ceiling. Those things are up there, if I weighed a little less I could probably do chin-up's on them!!
The inside edge of the cabinet bottom was simply placed on top of the conduit railing at first, then used some 2" TEK screws to 'toe nail' them into the metal, this was done through the door openings. While I'm still in construction phase, I am using these cabinets to store all kinds of things, most of my electrical wiring and stuff I have in one of them, first aid stuff, etc... They worked out very well!!