This tutorial series is designed to help developers use the Vonage Voice API with ASP.NET, focusing on playing audio to a caller during an incoming call. To complete this tutorial, developers need a Vonage API account and a virtual phone number. They must also configure their project by initializing Vonage with their API credentials and creating a public/private key pair. The tutorial covers how to create a stream NCCO, which is used to send audio to the caller, and how to play that audio during the call using an ASP.NET Core controller. The code includes methods for dynamically creating the NCCO file and saving it to a specific path.