If you have a new Amazon EC2 cloud server instance, and you want to host a public website on it, here are the steps:
(this applies to a Windows server, not a linux server):
1) From Amazon console, go to "Connect" and it will walk you through getting a password for the administrator user id.
For details, see this Amazon link:
http://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/EC2Win_GetStarted.html
2) Create an inbound firewall exception to allow web traffic to port 80.
This is under "security groups" in the AWS management console for your instance.
3) RDP to the new server and go to "server manager" and add a role of web server.
4) Get an elastic IP address from the AWS management console
5) Associate the elastic IP address to you EC2 instance in the AWS management console.