This tutorial guides on how to organize and associate incoming email attachments with each employee or vendor using Twilio SendGrid's Inbound Parse feature and ASP.NET Core. The process involves creating a Web API, configuring the application to receive files via email, storing them in different locations depending on the sender, subject, and file name, and adding Basic Authentication for security. The solution also includes future improvements such as ensuring uniqueness of filenames and retrieving rules from a database.