CircuitPython code uses libraries to simplify the programming process. Most code will only use a few specific libraries, but it's a good idea to download all of the them just in case.
Completing this step will equip you with the tools you need to build new projects going forward.
On the CircuitPython Libraries page, click the file name that matches the version number of the CircuitPython file you downloaded earlier.
For example - If your CircuitPython file was named:
Then you would download the library bundle named:
Inside of the library bundle, you'll see a folder named lib which contains a long list of code libraries you can use in your projects.
Libraries can be installed on the Circuit Playground Express by copying them to a folder named lib on the CIRCUITPY drive.