Step 22: Insert Batteries....
Insert 3xAAA batteries. I usually have most luck putting installing the center battery first, then putting in the side ones with the end that connects to the power rail going in first so it pushes against the rail. .
The rail that sticks out the front of the matrix goes to the positive side of the batteries, and the rail on the back goes to negative.
There should be 3 volts - 4.5 volts coming out of the batteries depending on how old they are. The Ognite can actually run on anything between about 2.1 volts and 5 volts. More than 5 volts will blow out the chip, and less than about 2.1 volts and the LEDs won't light up.