When you install RDS it disables the built-in remote access. Go to Control Panel, System and Security, System and click on Advanced system settings. On the remote tab, re-enable remote connections by selecting Allow remote connections to this computer radio button.
There is no more /console RDP switch since Windows Vista.
Yes, the Remote Desktop Services mmc snapins that you were used to in 2008 have been removed.
A Windows license grants you two "administrative" simultaneous remote desktop sessions before you need to install the Remote Desktop Services role with CALs. There is no "2 administrative connections +1 console (which would make 3 simultaneous interactive sessions)" though. It's just two. You can use the /admin switch with the Remote Desktop Client to avoid using up CALs when the RDS Session Host role is installed, but you can only have two admin connections at a time regardless.
From this Microsoft article which does a great job of explaining:
At any point in time, there can be two active remote administration sessions. To start a remote administration session, you must be a member of the Administrators group on the server to which you are connecting.
To RDP to a Windows Server 2012 VM hosted on Azure, you need to ensure that you have opened the endpoint in the Azure portal (think of it like a firewall ACL) in Azure, and also make sure RDP (port 3389-in) is allowed through the Windows Firewall as well. Then you need to make sure you're logging in with a user account who has 'Remote Desktop Users' privileges or better.
Next, disable the setting Restrict Remote Desktop Services users to a single Remote Desktop Services session by using the Group Policy Object Editor MMC-snapin to edit your Local Policy.
It's under Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Connections.
Run gpupdate after you make changes to the policy to apply them immediately.
I have a Server 2012 VM hosted on Azure, and I just followed the above steps, and now I am logged in twice, interactively, as the same user.
Best Answer
The CALs are not what is limiting you to 2 sessions. You need to go through the Remote Desktop Services installation process through Server Manager.
Here is an article from Microsoft about the process:
Remote Desktop Services (RDS) Quick Start Deployment for RemoteApp, Windows Server 2012 Style
After you go through the process there is a 120 day grace period before you need to install licensing.