What is AWS?
It is a cloud platform where we can do all computing related work. If we develop an app on our machine then it is not 100% sure that my app will be reliable and scalable. This is because my database will crash, memory get full, etc. Hence there are some limitations on local machines. To avoid this problem, we will switch to Cloud. Here the servers are known as Instances. As a DevOps engineer, we will use AWS cloud services to transfer an application from local to server. There are different types of services for different domains (You can refer under the services section once you login into the AWS console).
Also AWS works on "pay-as-you-go" model. It is a flexible payment system where customers only pay for what they use or consume.
Go on google and type "AWS Global Infrastructure". When you open the link, you will see a World Map. Inside the world map, when you hover on the dots you will see different types of colors for that dots. When you see Blue Dot, it will be known as Data Center or a Region. When you see red dot, that data center will be coming soon. Inside the Region, there are small shops where lot of servers are stored. That small shops will be known as "Availability Zone". To view this things in a graphical manner, visit this link