how to turn off maitenence required warning sign i...

Its on page 124 or your manual. If you don't have one here is what you do.
1. Make sure you odometer is showing the mileage, not trip A or trip B.
2. Turn the key to the on position (only so that all of the electronics turn on, don't start the engine.)
3. Push in, and hold, the knob that is next to the odoemeter (the trip reset knob)
4. 5 lines should show up on your odometer display. Continue to hold in the knob until all 5 lines disappear one by one and your light should be reset.

Best of luck.