I'm assuming you got an eGo starter kit? Does the battery look like this?
If so, you turn the battery on or off by clicking the fire button quickly (within 2 seconds) five times. The button should blink a few times. If you press and hold the button the fire button should glow if it is on and charged.
Now, should you press the button and hold it and it blinks, it means the battery is low on a charge and needs to be put on the charger for 2 - 3 hours to charge it back up.


ego charger and wall adaptor
The battery screws into the charger, and the charger's USB connector put into an USB/wall plug. The charger should have an indicator light that turns red when the battery is charging, and will blink as it checks the status of the battery. When the red light turns green, the battery is charged.
There is a video in the following link showing the operation of an ego battery:
A Good Starter Setup for a Beginning Vaper