MAZDA BT50 MODEL 2010?

I JUST NEW MAZDA PICKUP 2010 MODEL BT50. I HAVE PROBLEM IN 4 X 4.. DONT KNOW MUCH OF IT. WHAT SHOULD I USE WHEN DRIVING OR STUCK ON SAND. THERE AREA WERE I WORK IS DESERT AREA. DO I USE 4L OR 4H WHILE DRIVING IN SAND. AND WHAT TO USE WHEN I AM STUCK IN SAND. AND WHEN EVER I CHANGE THE SHIFT 4H OR 4L THERE IS A RFW INDICATOR FLASHES. DO I NEED TO OFF IT OR WHAT??