How long do I need to charge the device?

Ideally the device should be charged until it is between 80%-100%.

When the device is off you will see an indicator when you press the power button down, when the device is on you will see the battery icon in the top right corner which will change depending on how charged the battery is. There are many factors that contribute to battery life and charging time so it is not possible to put an exact time frame on how long it will need to charge, however, it is safe to leave it charging over night (in fact modern batteries are safe to leave plugged in indefinitely if that is what you would prefer).