In DAY 03, I start with a simple but super important concept: storage on AWS. I break it down into three categories—object storage, block storage, and file storage—so you understand where S3 fits. Object storage is where you store files as “objects” (images, videos, backups, logs), and in AWS the service for that is Amazon S3 (Simple Storage Service). I also explain the core S3 terminology you’ll hear in real companies: buckets (root-level containers) and objects (file + metadata). Plus, I highlight why S3 is so widely used—scalable, internet-accessible, and “11 9s” durability. Then we go fully hands-on in the AWS Console. I create an S3 bucket (and I show you the global-unique bucket naming rule), upload files, and discuss storage classes like Standard vs Infrequent Access vs Glacier-style tiers so you don’t overpay. After that, I show you how public access actually works: by default everything is private, so you must adjust Block Public Access and add a bucket policy (JSON) to allow anonymous read-only access using GetObject. Finally, I host a static website on S3 by enabling Static Website Hosting and uploading a simple index.html. I also enable bucket versioning and demonstrate how S3 keeps multiple variants of the same object—great for protection against accidental deletes/overwrites (with the tradeoff of slightly higher cost).