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

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.

Agree, these could be more likely causes than a gummed up core.  Since
the OP doesn't present any overheating problems or state underheating
problems, [except no heat from the core], I'd tend to think the vacuum
controls or a malfunctioning switch.