Remmina is a remote desktop client written in GTK+. Remmina supports multiple network protocols in an integrated and consistant user interface. Currently RDP, VNC, NX, XDMCP and SSH are supported.
Where is the setup documentation. If you are going to put an app out you should have good documentation on how to set it up step by step.
Same as for almost any Linux application distributed in source form:
There are detailed installation instructions in the archive.