This tutorial teaches how to redact Personal Identifiable Information (PII) from audio and video files using the AssemblyAI Python SDK. The process involves setting up an environment, transcribing the file, printing the redacted transcript, fetching the redacted audio file, and running the program. PII categories such as medical conditions, email addresses, and credit card numbers can be redacted from both audio/video files and their textual transcripts. The AssemblyAI API key is required for this process, which can be obtained for free.