You can skip to the final line for the needed command, or read through my journey on how I figured this out...
Fedora 20 is one of the easiest to use, most integrated distributions i've experienced. It was quite a surprise for me to find that establishing a simple RDP session would be so convoluted.
In a fresh installation, in software / utilities, you see a program called "Remote Desktop Viewer". Sure enough, RDP is listed as a protocol for connection. However, when you try using it, nothing happens...
turns out if you google around, this program does not support RDP currently...
But there have been previous programs that support this, such as rDesktop and tsclient. However, googling a bit more will tell you that what all the cool kids use now is Remmina with freeRDP.
So how do I install this program? well, with a "yum install remmina" of course! And it installs, but... wow, only SSH and SFTP connections?
Turns out you must install the rdp plugins. This is achieved with a "yum install remmina-plugins-rdp". But nothing happens on the client. Maybe I should close it and re-open it? WTH, it still doesn't display anything!
This post saved my life when I was about to fork into who knows what to get this working. It explains Remmina doesn't quit when you close it... so basically you have to kill the process for it to load the plugins (if you did it in the same order I did)
So, the true way to install this RDP viewer is
just do "yum install remmina-plugins-rdp" as it will install remmina as a requirement and load the RDP plugin correctly the first time you run it.
Hope it helps someone :) it's a good solution so far and offers quite a few options so i'm sticking with it.