We are all newbies, some have just been new for longer than others. In other words, we are all learning all the time.
I don’t know your station, but generally you need to set the differential so that your reading would be the same as other stations. Most readings are not absolute, but are relative - in other words, the reading you see is the reading that you get adjusted to what it would be at sea level at your location.
You usually have to set offsets for both your weather station console and your Weather Display software.
There are others here much more clued up than I am, but I hope this helps a bit.