Follow the circuit diagram above to reference the wires are connected. You will need to solder wires to the Trellis PCB and 4 potentiometers. Use male jumper on the Trellis wires to easily connect to the headers on the Leonardo.
The Trellis PCB will have 4 wires, SDA, SCL, GND and 5V that will connect the SDA, SCL, GND and 5V pins on the Arduino Leonardo.
The 4 pots have common ground and 5V power in series. The middle terminals connect the the A0-A3 pins on the Arduino Leonardo.
In order to control the trellis with the Arduino Leonardo, you will need to install the Trellis Arduino Library. Download Arduino IDE.
Open the Arduino library manager:
Search for the Adafruit Trellis library and install it
We also have a great tutorial on Arduino library installation at: