Newbie needs help getting GUI

[Peter Urban]

I installed Cygwin/X on an XP computer. I'm trying to connect to a
Redhat workstation that allows an SSH connection. Launching Cygwin, I
get the shell. Typing "ssh -Y - username hostname", I can successfully
connect to the workstation and get a shell. Pardon what may be a simple
question, but how do I get a GUI?

I'm a *NIX newbie, so please speak slowly and be gentle. I've
unsuccessfully tried to find the solution in the Cygwin documentation
and the FAQs and the mailing lists.

Thanks in advance for your help.

-Peter