The Electoral College Explained
This video from Ted-Ed explains the electoral college system in the U.S.
In the United States, the public does not elect the President and Vice President directly. Instead, when a majority of voters in a state vote for a certain candidate, that candidate receives that state's electoral college votes. The electoral college is "a group of people appointed by each state who formally elect the President and Vice President of the United States."
The number of electors is equal to the total voting membership of the house of representative (435) and the senate (100) with three extra delegates from Washington D.C. Each state receives a particular number of electoral college votes based on their population size. States with small populations like Vermont receive 3 electoral college votes, while states with larger populations receive many more; California receives 55 electoral college votes. Traditionally, candidates receive all the electoral college votes when they win that state.
When candidates run for the presidency, they try to "add up the electors in every state" to reach over half of the electors with 270 electoral college votes.
Supporters of the electoral college say that it gives smaller states power because candidates cannot completely ignore them. However, the electoral college can sometimes lead to situations where a candidate can win the popular vote but lose the electoral college - as has happened in the 2000 and 2016 elections.