Compiling SML requires Visual Studio 2017, later versions may cause issues!
First, use git to clone or download the SML repository The master branch is a copy of the latest built version and is generally considered stable. The development branch is a more updated version of SML that is used for testing new features. Generally you should try to be on the development branch, so you will need to do less recoding in the future and you can help test features as they are developed.
After you are done downloading/cloning the repo, open SatisfactoryModLoader.sln. VS will now allow you to build SML and ExampleMod, which is a documented example of how to use SML's features. You can code your mod in it directly or make a new project.