Take the blade and blade guards off the radial saw. Turn the saw motor 90 degrees so the blade shaft is facing directly down to the table.
Loosen the four corners of the table. The corners may be secured by hex screws, but this varies by manufacturer.
Place a flat metal object onto the surface of the table underneath the motor and lower the motor so the shaft is barely touching the metal.
Swing the motor over the surface of the table, both left and right and forward and backward, moving the flat metal surface with the motor. Watch the distance between the shaft and the metal to detect any discrepancies in the table; for example, any increase in distance will indicate a slope in the table.
After determining which corners need adjustments, place shims underneath those corners to even out the table. Recheck the table surface and make further adjustments as necessary. After the table is aligned, retighten the corners of the table. After tightening the corners, recheck the table again.