where can I find the stored files in amazon EFS

Or if you would prefer just browsing your EFS filesystem via simple web interface, here is one way to do that. https://aws.amazon.com/solutions/implementations/simple-file-manager-for-amazon-efs/

Your files on EFS will be stored on a EFS file system.

You can use the EFS Console to view the configuration but you have to use a host to access/view files such as attaching an EFS file system to an EC2

https://us-east-1.console.aws.amazon.com/efs/home?region=us-east-1#/file-systems