[Gimp-user] grayscale gradients

[Goosey <Goosey charter net>]

I'm trying to create a grayscale gradient that varies from one side to 
the other of a selected area but it doesn't show up when I finish the 
attempt.  I'm new to the concepts of Gimp so I'm sure it's some simple 
mistake.  Could someone detail how to do this?  Lol, from what i've read 
already, I think it can be done in multiple ways but any one that will 
work will suffice.  I'm sure I'm just missing an organizational detail.