editing config files

[gordonsmall User]

I am brand new to Ubuntu and the command line interface.  Years ago I
used DOS, but there has been a lot of water over the dam since then.
Anyway, I am trying to get my scanner (Epson Perfection 2450) to play
well with Ubuntu, and have been working thru manual installation on an
AMD 64 3800 machine.  One of the instructions is:

Edit the /etc/sane.d/dll.conf and enable the right driver for your
scanner. Look for the lines that say:


# The following backends are not part of the SANE distribution

# but are provided by the libsane-extras Debian package 


Below it are several commented out lines. Uncomment (delete the #) the
right one for your scanner.



How do you physically edit this file - I also have trouble finding it
after I installed it with the package manager.

Gordon Small