Sorry for the late response, I don't get notifications and did not check while being on holidays.
With the default settings/camera zoom is automatic:
When you just start it sits at zoom 1.00 and it follows your character.
After you build entities, the camera (base tracker actually) will make sure that your entire base fits in the screenshot. So zoom (and center position) will be adjusted automatically.
As for writing a guide: there is not much to write, by default (with an enabled camera) it will 'just work' (the demo video I made, was done without changing any settings)