HOW generally asks about the MANNER or METHOD of something:
How did you get here?
How are you today?
I'm fine, thanks.
HOW can be used with MUCH and MANY:
How much money do you have?
How many people know that?
HOW is used with ADJECTIVES:
How tall are you?
Six feet tall.
How hot is it?
It's very hot!
HOW LONG asks about a LENGTH OF TIME:
How long has she been a student?
HOW OFTEN asks about FREQUENCY:
How often do you practice the piano?
Two hours every day.
How often do you eat hamburgers?
HOW FAR asks about DISTANCE:
How far is your school from here?
About 1/2 a mile.
How far away is San Diego from here?
About 2 hours by car.