Head gasket problem. I thought putting in "stop leak" would have bought me some time. It didn't. The heater core started not working. I back flushed it several times. I had the head gaskets replaced as well as the radiator. I know need to replace the heater core. What is the easiest and fastest way to do this?

I replaced my radiator last year and back flushed the heater core and still cold air comes out. I know the heater core is bad. I bought a new one and would like to know the fastest and easiest way to replace it before winter. I had to replace the radiator because the head gasket was blown and I added "stop leak" to the radiator. I notice the air was getting cool and the radiator was getting hot.