I just moved into a beautiful home. I am currently a renter. There is a new concord 80 plus furnace installed. I know it needs a filter but I'm not for sure as to where it goes?

Usuall in the blower compartment or a place in the return air duct near the furnace.

HVAC is correct. The return plunum is the large rectangluar duct that reaches almost to the floor and then turns horizontally to enter the furnace box. There should be a trap door or slide tray in that short horizontal section. Match the dimensions of the new filter exactly with the old, no wiggle room here. This is what HVAC actually already said, I just changed the vocab a bit for non-HVAC folks.