The tutorial provides a step-by-step guide to storing files in Google Cloud Storage using PHP and the Flysystem library with the Google Cloud Storage adapter. To start, create a project directory structure, set up a Google Cloud Bucket, and create a private key for authentication. Then, install the required dependencies, list all files in the bucket, upload a file, rename a file, and delete a file. The tutorial also covers best practices and limitations of using Google Cloud Storage with PHP.