How to properly clean fog/mist

Can somebody explain how to properly use the defogger and defroster? What are their differences practically?

My windshield tend to get extremely foggy even in summer and it get extremely dangerous to drive. I tried multiple combinations, advices, trips and tricks but I'm not sure about the best approach. I see people advise both defogger and defroster. Either none of them works or I cannot get them to clear my windshield.

Please do mention details like which one to use, what temperature should I put, should I do anything with ventilation or air circulation, should I do anything with the windows. And how long should I expect it'll take to get the windshield clear?

I have seen different opinions about using defog/defrost and cold/hot settings. Can anybody actually explain what is the way to go?