While it probably won’t make sense for you to become an expert in HVAC (to do it the way we do it takes about 20 years to master), it will be useful to have a sense of the main working parts of the system.  If you’re not familiar, here is the basic layout of a forced air system.  The thermostat will trigger the system to start and stop, and the duct work will carry the conditioned air throughout your home.