How to deploy Magento on multiple EC2 instances with load balancer

I want to start my own mageno store on amazon cloud, but Im having trouble understanding how to deploy magento on several differnt EC2 instances to use with load balancer.

From my understanding, I need my application(in this case magento) to be copied to all instances and the load balancer will route users to the appropriate instance. so how do I do it?

Do I need to setup my store on one instance then duplicate it?

Thanks