Adafruit Feather - Gravity I2C ADC Module

Hi, I am trying to interface an Adafruit Feather with some Gravity sensors, and from what I understand, the I2C ADC module should be able to do this in a much more straightforward way. The wiki gives instructions for an Arduino Uno equivalent, but as I am an Arduino newbie, I don't really know how to wire it for the Feather. Any help would be appreciated.
Here is the link to the aforementioned wiki page: DFRobot Wiki
Here is the link to a pinout diagram for the Feather: Adafruit Tutorials
The Gravity modules I am trying to interface are the soil moisture sensor (capacitive) and the 5A digital relay for a pump. The moisture sensor should be fine with the ADC module since it is simply being read, but do I have to worry about anything for the relay?
Here is the link to the aforementioned wiki page: DFRobot Wiki
Here is the link to a pinout diagram for the Feather: Adafruit Tutorials
The Gravity modules I am trying to interface are the soil moisture sensor (capacitive) and the 5A digital relay for a pump. The moisture sensor should be fine with the ADC module since it is simply being read, but do I have to worry about anything for the relay?