It shouldn't be confusing. The only reason it is confusing, is due to the original question asked. We are talking about terminal servers, which Microsoft now refers to as the Remote Desktop Services. You use RDP to access an app on the server hosting Remote Desktop Services.
Remote Desktop Services cannot be hosted on a server which has the domain controller so you will need two servers.
So you have Windows Server 2012 R2 or Essentials. You purchase a license which allows the Domain controller, Hyper-V host and remote services. (again remote services must be on a separate server).
OK, so now you have your regular server which contains the SQL databases and domain controller, etc. Remote Desktop Services is on a separate server (Remote Desktop Server) and hosts Amazing Charts application. Now each USER (no matter what type of user) can access an instance of Amazing Charts on the Remote Desktop Server using RDP. Each user must have a license to access that app. Simply think of AC on the Remote Desktop Services located on the separate server as a client except an unlimited amount of users can access the app. The beauty of this, like Sandeep pointed out) is if you set up your office like this and then one day set up another office (instead of getting another thread on how best to set this up), you simply set up the other office with thin clients or computers and Internet. They then use RDP on their computer to access the AC app. It is like AC is on their computer. But, the user at the other office must have a license. Each user which accesses any app on the Remote Desktop Services computer (aka Terminal Server in the past), MUST have a license. If, as the author states, you use one RDP for more than one user, this is considered abuse of the Microsoft EULA and Microsoft could potentially take your server OS and all the data. They likely wouldn't. They would likely send a very strong letter telling you to purchase licenses.
FORGET ABOUT RDP FROM HOME OR YOUR PHONE OR TABLET. THAT DOES NOT REQUIRE A LICENSE. IF YOU USE RDP TO ACCESS THE APP ON THE REMOTE DESKTOP SERVER, YOU WOULD NEED A LICENSE.
