I created a page with a simple guide on how to add a virtual machine to Microsoft Azure. This, however, is not instruction on doing this from within the Azure Portal. The VM is added by using the cloud shell.
I wrote a quick overview on a new Azure Cloud Shell set up. This shell allows for command line access to Azure from within a web browser. Although the web-based Azure Portal is preferred for Azure work, due to its ease of use, there are times when CLI is needed. It is a very useful feature or tool. Read the Overview here.