It's quite simple!
- Firstly, place the orbit in between the two battery opening tools.
- Then twist the top battery tool anti-clockwise to open
- Open the Orbit and detach the old battery from the inner casing.
- Place the new battery with the plus symbol (+) facing downwards.
- Push the top and bottom Orbit shell together. Then place the Orbit in between the opening tool. Twist clockwise to lock the Orbit close.
Below is a link to a video on how to change the Orbit Keys battery: