Q. How do I print my pamphlet on both sides of the paper so that I can fold it as a Tri-fold?

When printing a pamphlet the page orientation should be "Landscape".

To print it from the Color printer in the Library Lab

Select File > Print > Choose the HPLJ Color 500 Printer

Select the down arrow next to Print One Sided and choose Print on Both Sides, Flip pages on short Edge

That's all you need to do and it will print it as laid out for you to fold the pamphlet.