It should be relatively easy to check if you have flow through the heater core. The fact that both inlet and outlet hoses are hot would suggest that there is sufficient flow. First, verify that the aux pump is actually running. To do that, just turn the ignition on without starting the engine. The pump should turn on. If the pump runs, then disconnect the outlet hose from the heater core, start the engine and see if coolant flows out of the outlet. Catch the coolant with a small cup or bucket and shut the engine off once you know if there is flow or not.
The heater knob controls a door/damper that directs more or less flow of air through the heater core. If that connection and damper is not working correctly, then the flow of coolant through the core it irrelevant. You can use my interior DIYs to get at the HVAC controls to see if things are working as they should.