You should be able to start CUPS with the following:
I am not sure the number for cups. Also, I use mandrake so this may be a little different for Slack. I am also not sure how Slack sets up services for bootup. The hard way to do it would be configuring the /etc/services file if Slack uses one.
Once it is started try connecting to it via your browser: http://localhost:631.
You should be able to add/manage printers from there directly.