Pausing With Sensor

I am trying to alter the function of the rain sensor part of code to use the pause function instead of the standard rain delay.

As far as modifying the firmware, is the Main.cpp the only place to edit? Sorry I am a bit new to arduino/coding.

I dont have the hardware yet, but I understand the rain sensor(sn1) can take a digital high/low signal. is there a voltage limit on this? I assume I will use 5v from the vin port.