Replacing the JBL GO 3 Battery (How to in 4K)

We are describing the process of the battery replacement on a JBL GO 3 portable Bluetooth speaker.
This speaker is waterproof, so it takes a little bit more effort to gain access to the inside of the speaker. But luckily we can do so still with very limited tools.
We are giving easy step-by-step instructions so you can do this repair yourself.
Good luck!