Trusted publishing using Azure blobs is really quite straightforward.
This page is really just here to point to the S3 instructions because everything is basically the same.
You need a GCS_CREDENTIALS_PATH environment variable. It points to the location of your service account JSON credentials file. Other than that, there's no additional setup — just use of gs:// instead of sftp:// or s3:// in config/config.ini or when you add content with FileManager or PathsManager.