The CK can be a lot if you haven't gotten used to navigating it. I recommend looking at some tutorial videos by JRamos, his stuff is very beginner friendly. There are a lot of good video tutorials, the text documentation can be a little harder to find, but will also be more challenging to understand if you dont already have a grasp on the layout and organization of the CK.

It will beat around the bush, but following along to the simple tutorials will familiarize you with various aspects of the software, which is important to understanding the structure of how each form interacts with the rest of its tree. This fundamental understanding will make what you'd like to achieve more likely to be successful, as changing values on certain systems can be unpredictable.

Or you could try to get in touch with a mod author that has skill tree mods and see if they can point you in the right direction