The buttons on the Smart Lighting System from top down - on our 575 but similar to your vessel-

 

Top - On/Off button

S1 - program number 1 button - used to turn on the lights you /yard have programmed to be controlled by this button at the intensity /brightness also programmed eg could be programmed to turn on central lights and strip lights at say 50% intensity.

S2- as per S1 but this is a second program

To program these buttons - turn the lights on which you want programmed, select the intensity and then press and hold the S1 or S2 buttons until all the lights flash. The program is then set. 

Lower 4 buttons are to turn on sets of lights and are used as the dimmers.

eg top left button - to turn on round central down lights - press and hold twice to dim, press again and hold to increase light.

top right - to turn on recessed (ceiling and floor) and central LED strip lights - press and hold twice to dim etc

Lower left (star pattern) to turn on the recessed red LED floor light at the bottom of the stairs and also at floor level in the cockpit. No dimming function.

Lower right- to turn on lights over the galley area - dimming as normal.

 

The only other light switch is on the deckhead (ceiling) to starboard as you come down the stairs. This controls the two ceiling down lights near the stairs so you can see as you walk down the stairs and can see to get to the SLS control.

 

I was not shown the operation or received a manual for these lights. Just picked it up from trial, error and persistence. But I think the above covers the operation.