Powering the Arduino Mega with a Lithium Battery

Step 4 Connect the wires into the Arduino Mega

Now, connect the ground and power wires from the Mega backpack into the Arduino Mega. The ground wire (blue in the picture) should be inserted into the Arduino Mega's GND pin on the upper right row of headers, and the +5 volt wire (red in the picture) should be connected to the Arduino Mega's 5V pin.