Question 1:

How do I insert and remove the flex PCB cable?

Question 2:

I wish to run it with a battery - how do I do that?

The following battery will fit perfectly within the case, and should be connected to the white connecter. Link to battery here

Question 3:

Where is the code kept and how can I contribute to it?

Below is a link to the repositories. If you’d like to collaborate on this project, have a look at the issues existing in each of the repositories and create a pull request to solve one, or create an issue of your own.