Where is the intake or the exhuast pipe on my goodman furnace?

Depends on the AFUE of the furnace. 90+ will have 2 plastic pipes at the front of the heater and they will go up and exit the exterior wall. 1 line is intake, 1 exhaust. 80% will have a single metal flue vent pipe that goes up through the roof. There is no intake pipe, it draws air from the house.