Gimp configuration

[Alex Miller]

Hello,

I am trying to configure GIMP but it
comes to a point where it is asking
me use rulers for my screen.

I am sure that the use of this dialog
is obvious, but for some reason I
am being too dyslexic to get it. Do I
read the ruler and enter it's length?
How do I know which units?

Ok, I know I'm being a bit dense but
it happens.

Alex Miller