Or just read Samuelson's or Mankiw's Intro Econ textbook. There's a reason those 2 are used everywhere from AP Econ all the way to intro Econ classes at MIT and Harvard.
As to why the mankiw book is used at Harvard… maybe we should have a talk about monopolies… ;)
That’s just a joke it’s a good textbook but its status as the standard at Harvard is only partially related to its quality.