Help with creating UI mod

[Rukongai]

So I am completely new to modding, this is the first time I've looked into this at all, but I have an idea and I would like to see if I can make it. I have some experience with Unity, Blender and coding so I have some of the basics down at least. I want to create a UI element basically, something like the Docking Port Alignment Indicator and Lazer Docking cam mods do but I have no idea how to go about it. I don't even know how it works exactly or how stuff like that displays on the screen. Obviously I have a big trip to make in order to reach the point I want, but I can't find any sources to help me in this trip, so if there are any suggestions or sources you can provide it would be awesome. Thanks a lot for your help!

[wasml]

Unfortunately official documentation is scarce - the API doc is here -  mostly a list of methods and fields with a (very) few comments. Other than that mod source code and some tutorials are your best hope. Note that many of the tutorials are rather old but many are still relevant with a few exceptions (like wheels - I forget which version changed the setup).