The heater hoses to the heater core are about a 3/4 diameter rubber hose coming off the back of the engine behind the altenator. You have to get a splicing T and install it in one of the heater hoses to flush the cooling system out.
There might be a trim panel covering a relay center on the fire wall - remove the panel and it should give you a better view to where the heater hoses connect to the heater core. If your thinking of changing the hoses be careful pulling on the hoses at the core connection points, they are plastic tubes and could crack in half, then your buying a new heater core. It be best to cut the hose off around the heater core connections if you plan to remove them.
Another reason you may not be getting heat is your thermostat could be stuck, there may be a broken vaccum hose or one of the blend doors or vacuums motor in the heater unit could be malfunctioning.
good luck
harryface