Flushing the coolant system and changing the coolant

What is your question?

I want to change the coolant myself. I think it needs to be flushed before adding new coolant. There appears to be a breakdown of the dex-cool. It is overdue on this change I admit. I had a bad experience on a Honda I had once. Is there any ports..drains,etc. that need to be opened to make sure that air is out of the cylinder heads when filling with new coolant? Also need to change the thermostat.