http://www.cups.org/documentation.php
i can give you the "big picture"...
basically, you install cups (unless it's already installed - it usually is), and then you start it:
on slackware the startup script is
/etc/rc.d/rc.cups
you can also use
pkgtool to make cups run on system startup...
in
pkgtool, you just need to go into
setup and then
services - then just make sure
rc.cups is selected...
once the cups daemon is running, you can open a browser and go to:
http://localhost:631
there you'll be able to set-everything-up...
=)
by the way, if you did a slackware default full-install, cups should already be installed...
you can check if it's installed with:
ls /var/log/packages/ | grep cups
and you can check if it's running with:
ps aux | grep cupsd