We replace our heater this winter and now the central is not hook up I have 2 wires that come from the unit outside where or what do I hook them too? It is a heil N9mp1 gas hot air furance

First off, I would contact the installer, they should be able to come and hook up the system quickly.

That said, the two wires outside hook to the two wires coming off the contactor coil. The two wires inside the furnace hook to why and c on the control board. Really, its as simple as that, but, I really would have the installer come back and do this because mis-steps can cause damage to the low voltage electrical system. Good luck and please do let us know how things work out.