Now that we've seen servers (EC2) and storage (S3/EBS), it's time to look at the "neighborhood" they live in. The private network space where your resources live together inside the cloud is exactly the VPC. CLF-C02 doesn't dig deep into networking, but it will absolutely ask about the basic skeleton: "what a VPC is, and how subnets, security groups, and the internet gateway fit together."
Today, using the analogy of building a house, we'll lay out the four networking parts at an intro level — the VPC (the land), subnets (the rooms), the internet gateway (the front gate), and security groups (the gatekeeper).