AtThere are six green switches at the bottom left corner there are green switchesof the board, visible on this FlightGear screenshot:
Which are visible onDetails of this Flightgear screenshotanti-ice section, from actual aircraft:
"W/S" is for windshield. You can send hot bleed air intoonto the windshield surface with the W/S BLEED switch and anti-ice fluid with W/S ALCOHOL.
Someone asked the same question on Flightgear forum.