I had the same problem as the OP, and thanks to the advice of several posters here, I now have my HP printer running. (Canon and Dell/Samsung to come.)
Summary: CUPS wasn't running - made rc.cups executable - started rc.cups - opened HP Device Manager from the main menu - added my HP printer - successfully printed test page.
I didn't get to a solution with just this
https://docs.slackware.com/slackbookrinting
But I also hadn't yet found these two linked in this thread
https://docs.slackware.com/howtos:ne...e_print_server
https://wiki.alienbase.nl/doku.php?id=slackware:cups
So now I have more to learn from
To everyone who posted help - THANK YOU!
TKS
Edit: after getting my HP printer to print - in Printers, Canon inkjet and Dell/Samsung laser printers were recognized immediately. For the Dell/Samsung, a generic driver was suggested, but openprinting.org had a more specific one. Test pages printed successfully.