Figure out the difference between 2992 and current altimeter setting. Drop the decimal point and add a zero to the end. Then add or subtract the figure to field elevation. Example (30.22 (current setting) - 29.92 = .30) drop decimal point to eqaul 30, then add zero to the end which equals, 300. Since pressure is higher than normal subtract the 300 from the field elevation to give you your pressure altitude. So if your field elevation was 1200 ft, you pressure altitude would be 900 (1200-300=900 ft) The current pressure therefore simulates that you are at 900 even though the actual elevation is 1200. Hope this makes sense.