I am going to be flushing my heater core, I see both hoses going into the firewall one on top and one on the bottom but I cant figure out what one is the inlet anf what one is the outlet. Can anyone help me out please?

The heater core inlet comes from the engine block. The outlet goes to the water pump.

you cut the heater hose put your flush tee in it and it comes with the adapter to your hose it comes in a kit..on my malibu i put 2 flust tee's in each heater hose.when you hook it up leave car running so it can push the water in your radiator also it cleans most of all your hoses and radiater and heater hoses....