Download the repository, the included submodules (git submodule update --init --recursive), the listed dependencies and set the $(BAKKESMODSDK) macro to your BakkesMod SDK location,
after which you can start the project through source/RocketPlugin.sln.
The Debug configuration builds the plugin with additional debug logs and loads the generated DLL directly in Rocket League with bakkes_patchplugin.py, which comes by default with the BakkesMod SDK.
warning: when building this will overwrite your original RocketPlugin.dll.
The Debug configuration builds the plugin without debug logs.