Look to the right of the battery for a small black switch.

Slide the right side switch to the right, away from the battery.

When the switch is in the correct position, a red sticker will be visible underneath the switch.

On the left side of the battery is another black switch. Slide this to the left, away from the battery, and hold it in place there.

The left side switch does not have a red sticker underneath.

Slide the battery towards yourself.