To use any scripts, you need credentials for Google APIs. Create and download OAuth 2.0 credentials at Google Developer Console. Store the credentials.json in the same directory as the script files.
When running a script the first time, it will require account authorization to access the Google API. This will create a token.pickle file in the same directory as the script files. Once created, the script will automatically use the credentials stored in the token.pickle file for subsequent runs.