The T-slot cover snaps securely into the slot after the wires are in place. The wire clips are inserted in the slot and twisted clockwise with a pliers to lock into place. I cut some of the clips with a side cutter so I could slip the wires in from the side rather than threading them through the holes. Caution: Do not bundle the limit switch wires tightly with the stepper power wires. Currents induced in the limit switch circuits will cause erratic operation with RAMPS. The photo showing the black and white wires zip tied to the bundle is an appropriate application.