How do I correctly flush my radiator? Replaced the water pump and the thermostat and the car doesn't blow hot air inside the cabin?!?! Also I am a women so steps would be awesome:)

Flushing the radiator isn't all that difficult. Most flushes have instructions right on the container.
All you need to do is add the flush to the system, run the engine for as long as the instructions say.
After running the engine, I generally remove the lower hose where it connects with the engine and let it drain from there (larger chunks of debris don't come through the regular drain very well). Be careful removing the hose. Don't do it 'till the engine cools down a bit and be careful not to get any in your face and definitely rinse your hands off right away because the flush chems are caustic.
After using the chemicals, fill the system with water (some chem kits use a neutralizer if so, add that)
run the engine and repeat. Drain and re-fill two more times to get any remaining flush out.
You can also remove the two heater hoses...run a garden hose into either end to remove debris in the heater core.
Once everything is back together, fill the system with 50/50 mix of antifreeze and check the mixture with a hydrometer (cheap ones are available at parts stores).
When re-filling, run the heater on high heat. It's best to shut the engine off just before it reaches normal temp and wait about five minutes. That allows the thermostat to open. Then re-start and continue filling.
Some engines have bleed screws at different locations. (check chilton or haynes manuals for location of those). Bleed screws permit trapped air to leave the system.
Be aware...If the engine previously overheated it could have caused your head gasket(s) to fail.
If you have steam from the tailpipe, coolant in the engine oil or oil in the coolant (any of these...they all don't always happen) have the system checked for hydrocarbons. Hydrocarbons are combustion products and if found in the cooling system it indicated HG failure...combustion gasses will collect in the heater and prevent it from working.
If your engine isn't overheating but the heater isn't working, try running the engine with the cap removed and follow re-fill instructions I provided... thesystem may not be obstructed but may be air bound.
Any questions, just ask!!