If you're getting a rear cabling option for your interface module, and you are installing into an enclosure, you may want to pick up a pre-drilled panel to make sure you get a clean installation.
Typically, you'd cut a square in your enclosure and drill 4 of holes for the mounting screws. Attach your DB-25 connectors and then mount the panel to your enclosure.
Due to the variability of possible installations, this does not include any screws. You are just purchasing the panel.