The game has been out for a week, there are no guides on ANYTHING. That said, here's my recommendations on how to get started:
First, download ModBuddy. This is the tool you will be using to create, debug, and compile mods. Open up Steam, hover over the Library tab button, and go down and select Tools. Then find the Civilization Beyond Earth SDK, and download it. Congratulations! When you run the SDK, you will see two options; for FireTuner, a more advanced LuA code editor, and ModBuddy, the basic XML-based mod compiling tool that all Civ modders need.
Second, read Kael's Modding Guide, specifically all the way from the start to the end of Add a Trait section. It is for Civ 5, and it is heavily outdated, but it is still the best resource on how to mod Civlilzation games. Civ: BE is very similar to Civ 5, and alot of what he says still applies.
Third, download a Sponsor mod from the Steam Workshop and poke around in it - modify their starting units, their leader's model from Hutama to Kozlov, etc. I would recommend donald23's North European Space Organization mod, as he put helpful comments into the code of his mod for beginners. His mod was also the first Sponsor mod created for Beyond Earth, so you can be assured he knows what he's doing.
Then try your hand at creating a Sponsor yourself. Download a sponsor mod, and copy all the files into ModBuddy. Go through each one slowly, modifying the files to your liking, and come back to this thread if you need any help. Or add me on Steam, I started modding with Civ: BE too and I am doing the exact same thing you are, so I could be of some use. My Steam name is Cannon Fodder.