[ale] novice question

[William Mahavier]

I want to be able to view in X nroff files. Using apropos I found
gs and the man page sounded like it should do the job but when I try
gs in a console window I get: svgalib: Cannot get I/O permissions.
and when I try on X I get:
Not running in graphicscapable virtual console.

I do not know what these messages mean or how to find out. I did
find a package that contain ghostview that came with my slackware
distribution.

Finally my question: Is ghostview what I need? 
If so what do I read to find out how in install it?
The file I have is gnuzipped and tarred and contains ghostview.
Do I just untar it in / as root?

Thanks, Bill