You should have your API key created. This can be found from the Developer Dashboard. Depending upon your package, your API key will provide you with access to specific datasets. If you do not have a paid package, sample data will be returned so that you can develop to the test data prior to going into production. If you have a paid package, live data will be returned if available.
If you have not purchased a package or data is not available yet, you can use the API key of TEST to retrieve sample data. For example, if you wanted to retrieve playoff projections but the playoff teams have not yet been determined, you can use the TEST key to retrieve test data that you can develop against.
All calls can be made using GET requests. The URL structure consists of the domain, API version, sport, and then the requested resource. Your API key should be sent as a GET variable.
The URL above will return all NFL teams. The specific resources are available under the appropriate sport. A list of available sports are below.