@22689742 Jas, thank you for your question.
The document that you linked to would be if you are using one of our non container products (like a blessed linux image). Since you are using a container, there are different steps that must be follow to use SSH. With a custom container, you must first go through the process of enabling SSH. Please see here for more information how to do so.
Once you have enabled SSH for your container, you should be able to then follow these steps. Please note that using a remote shell (az cli) is currently in public preview, which means it's not considered ready for General Availability (GA). If you have issues using it, we request you attempt SSH via a browser until remote shell access goes GA.
Let us know if you have any other questions.