API_URL is just the url of your institution. For example,
API_URL = "https://example.edu"
API_KEY is an access token. you can create one manually through the Canvas LMS user interface. Go to Account > Settings, then scroll down to the “Approved Integrations” section and click the “New Access Token” button.
Our troubleshooting page provides examples of what a valid URL might look like, and directions on how to create an access token.
If you have any further questions, please feel free to create an issue on GitHub or join the #canvasapi channel in the UCF Open Source Slack