This should set the GEODE_SDK environment variable, which you can test after restarting your terminal:
echo %GEODE_SDK%
If that command prints out the path you installed the SDK to, then it has worked correctly.To develop mods, you will either need to build Geode from source, or install prebuilt binaries using the following command:
It is highly recommended to set the CPM_SOURCE_CACHE environment variable. This will prevent CMake from flooding your filesystem with duplicates of the same repositories, and allow you to build mods offline (given you have built them online at least once).
To do this, create a directory somewhere permanent, and set the environment variable CPM_SOURCE_CACHE to the full path to that folder.