Very simlple explaination for very basic version management please...

I grew up with MS-Dos, know the basics to several languages and do complex micro electronic projects as a hobby, but when I´m googling that subject I feel completely illiterate… and I mean it!

I´m using the 3D-Printer firmware Marlin here on GitHub that is being very actively developed and since I love playing around with experimental features I like to update regularly. My problem is that a basic setup for my printer involves around 100 lines of code spread through multiple configuration files that cant just be carried over 1:1.

I’ve read, in order not to need to start over at zero every time again, looking up and changing every single setting over and over again I could “just” use version management…

The problem is, that I´ve already spent hours on google, finding only guides I cant comprehend since I´ve never worked with git (only used github to download and upload manually) and just started out with Visual Studio Code.

The only thing I need to be able to do is update my local project files (including the ones with changes I made) without having to set up everything from scratch again.

Is there a simple step by step process somebody here could lay out for me? (Using Visual Studio Code with PlatformIO, project: https://github.com/MarlinFirmware/Marlin/tree/bugfix-2.0.x). I would even name my firstborn after you for that!

If thats not possible because of complexity, could you point me to the most efficient learning path to get to where I need to be?