To build an event management app with Laravel and Twilio SendGrid, you need to create a new Laravel application, set up authentication with Laravel Breeze, and integrate Twilio SendGrid for email notifications. You'll also need to create models, migrations, and controllers for events, registrations, and users, as well as add routing configurations and Mailable classes for emails. The app should have views for creating, editing, and viewing events, as well as a dashboard for managing events created by the currently logged-in user. Finally, you'll test the app to ensure it works properly and explore Twilio SendGrid's advanced features like email analytics and templates.