How it works
In order to access the API specs and tools, you need to sign up. Wait for a a confirmation e-mail confirming your access. Check your spam folder in case it does not arrive
To generate your Client ID and Client Secret you need to add an app in My apps. To add an application you need to enter its name, add a description (optional) and OAuth Redirect UI (optional). After successfully adding your application you will get your Client ID and Client Secret. Copy and store them in a safe place.
You are now ready to test your application. Review the documentation and learn how to start using the APIs