Here is a quick video on how to add a printer to Darkroom Core.
Darkroom Pro and Core include built in drivers for most popular
photo printers. If you do not see your printer listed, but have Windows
drivers for it, you can still use the printer with Darkroom software if
you set it up as a Windows printer.
Open your Darkroom Software.
Click on the Setup tab.
Click on Printer Options, then Add Printer.
Scroll down the list of printers and near the bottom, select Windows Printer.
Set any options you want, including those in the properties dialog.
Ensure that “Enable Driver” is checked
Click OK. You should see your printer listed with a Windows icon next to it.