programming error...Need Help!!

Well this is what the potentiometer should do according to the instructions:

You can rotate the potentiometer on the board to change the watering threshold value. Once the
soil moisture value reaches the threshold value, the system will start to water the plant.

The potentiometer is to set the watering threshold value according to the following range of analog values received from the soil moisture sensor :
0 ~300 : dry soil
300~700 : humid soil
700~950 : in water
So it would be preferable to set the watering threshold to 700~950 : in water!

And for the

    flower.SerialSet(MoistureSensor);
    //get the settings from the PC software and the moisture value

....I found this code in the library in sunflower.cpp found in the AFWS sample code that i mentioned above and i was wondering if this is the part of the code that gets the settings from the PC software and the moisture value too

  void sunflower::moisture()
    {
          humidity=analogRead(3);
          dat2=humidity/500*100;
    }

What does SerialSet mean here?

Can you tell me how should i introduce these in sunflower.cpp and in sunflower.h library files in the AFWS Sample Code(Arduino) mentioned in the link?