HP Laser 5m Printing Problem?

I enjoy just purchased an HP laser 5M from ebay, i be told that it would be able to print front and wager on copies since it came beside the item number c3920a attachment. But i am having problems trying to integer out how to print double sided pages. does anyone enjoy and idea how to do it?

HP Laser 5m Printing Problem?

Here's a guide that'll put your foot you through the whole process.
You might try going to HP's website and downloading the user booklet.