This document presents a comprehensive guide on scaling applications using AWS, detailing best practices for managing infrastructure as user demand grows from the first user to over 10 million. Key strategies discussed include the use of AWS services like Amazon EC2, RDS, DynamoDB, and Elastic Load Balancing, along with recommendations for data management and performance optimization. The author emphasizes the importance of monitoring, automation, and adopting a service-oriented architecture to manage complexity and enhance scalability.