Measurement of Air Pressure, Temp. & Altitude
The sensor is located at the red rectangle position. Press keypad "2" to measure.

Hints on calibration for the altitude:
Need proper calibration for the altitude (A). You should first select Weather from the lower right menu and then find the sea-level air pressure of your nearby place from the webpage. Finally, select Calibrate (or press keypad "D#") to input the sea-level air pressure in hPa.