I was ... at one point in time ... able to set up subnets within my Azure Virtual Network Environment. And now, sadly, I cannot find where or how I did that.
I thought it was under the network's menu in the configuration tab ... but this just freezes out on me. I know I still have the subnets I created because I have machines in those subnets that work ... however ... I can't seem to access the page where they are created to make additional ones.