There are three sets of light on the tablet. 

The first set you will see once you plug in the tablet. They are the four crop marks to the active area of the tablet

The other two are located at the top of the tablet to the right of the USB connection. 

They are the Wireless connection light (two states: Breathing Blue, looking for a connection, and Solid Blue - connected) and the power light (Solid Green - On) not on, the tablet is turned off, or not receiving power.

The Blue light on the left shows the wireless light as solid and connected.

The Green light on the right shows the power light and the tablet as being fully powered and On