Postman is used to collaborate on APIs, including the Async Audio API and Conversation API. To start, retrieve your credentials by clicking on the "Generate Token(Authenticate)" option in Postman, which will provide an access token that can be used for authentication. Next, upload an audio file using the Async Audio API, specifying the content type as "audio/mpeg" and selecting a mono-channel mp3 or wav file. After processing, you'll receive a Conversation ID, which can then be used to retrieve the transcription from the Conversation API by clicking on "Get Messages (Transcript)" in Postman. If you don't see any results, give the system 1 minute to process before trying again. Additionally, you can use the Get Insights feature to view insights from the audio clip uploaded.