How to use the ECS instance as an operation system

I’ve created a ECS instance with VPC, connected to it and successfully entered as root, but now I cannot start an OS usage. Is it simple or possible to do from VPC-connection to the ECS instance? Or what is the correct or simple way to do it?
I’ve read a lot of documentation on the site but haven’t find any clue about that.

what are you exactly talking about? ssh connection? or how to operate installed OS in ECS?