Ansible collects groups of known hosts in its inventory -- a .INI-style text file. You can either add your hosts to the default, or create a separate inventory file and tell the Ansible command line utilities to make use of it.
For our example, we'll create a file called ansible-hosts and define our Cloudshell group and hosts there:
[odroid_headless] 192.168.1.11 192.168.1.12 192.168.1.13
Now we have our inventory, which contains a group called odroid_headless, which contains three hosts. We could have just as easily used DNS names here, but IP addresses are fine too.