Yes Darkwood is totally correct, I tend personally to wire to one light via a plug in ceiling rose from 20 amp rated switches, it is usually an emergency and closest to the switches and a 3 core and earth supplied to it from the switch, you may also require a 2 core for a retractable switch for dimming, so 5 cores may be required, keep the 3 core and twin apart as the voltages will be different, and then the other lights do plug into from that first light in sequence, you will need to allow 2 things not mentioned, your time to spend with the Thorlux engineer when he commissions, and your time spending with the client which I call staff training. Otherwise it is actually very simple, it is very likely remote controls will be supplied for the system too, allow for extra batteries and for fixing the bracket for the remote to the wall, silly little things but training the staff and fixing the remote may get you some brownie points, the after service from Thorlux is incredible, but then it should be at their prices ha ha