Hi@akhtar,
There are different ways to run docker inside docker container. One way is, you can manually install docker inside your container. But the easier way is you can share or mount your local docker engine inside docker container. Use the below given command to implement this task.
$ docker run -it -v /var/run/docker.sock:/var/run/docker.sock --name os1 imahe_name
Now you can run docker commands inside your docker container.