How do presidents use the electoral college

They pander to swing states and underpopulated states disproportionately while ignoring territories. Well, smart and cynical ones do, that is.

Yes, it is how the President is elected. There are 538 "electoral votes". (100 senators, plus 435 congresspeople, plus 3 electoral votes for Washington D.C.). Most states are a winner-take-all system based on who wins the popular vote of that state. For example, Oregon has 2 Senators and 5 congresspeople. Whichever candidate has the most popular votes in Oregon in November, (the first Tuesday after the first Monday is election day), will win all "7" electoral votes. The first presidential candidate to receive 270 electoral votes is elected president. (That is 1/2 of 538= 269 + 1= 270. It will stay this way unless a constitutional amendment changes the "electoral college" system to the popular vote.