In this page you will find three different videos that will guide you through different procedures.
How to sign-in to the API portal and test an API?
How to register an API in Azure AD?
In this video you will see how you can register your API (called "testApplication" in this video) with Azure Active Directory. After the API is registered as an app in Azure Active directory, you must create App role as shown. In the Properties, select Assignment required. This ensures that only the client apps that are allowed API Permission can get access token for your API.
How to register a client Application and get Permission to use an API that is registered in Azure AD?