Your XO needs power to run. Power is electricity, and there are two ways for your XO to get it: from its battery or from a power cord.
Using battery power
Plugging in your XO
When to charge the battery
Caring for your XO
Viewing the XO screen in sunlight and adjusting the volume
Being safe with the XO
Copying the XO contents (backing up)
Conserving disk space
Getting support for your XO