CGP Grey on Youtube did a great video explaining this. From what he’s said, individual votes still matter; but part of the electoral college means that if you live in certain states, your vote essentially means more than the vote of someone in a different state. That’s how, very occasionally, it is possible for a president to get “voted in” when they technically had fewer votes than the opposition. It depends which states voted for who. Apparently, the logic was that it was supposed to stop politicians from only paying attention to a tiny fraction of states (aka the biggest ones); but it doesn’t really work that way, and CGP clearly demonstrates and explains exactly why it doesn’t work as intended.
Worth noting that a lot of other countries that also use that style of voting don’t have an electoral college at all. So it’s not a necessary feature or anything. My country has no electoral college, and our vote is worth the same no matter where we live. But then, our population is also a lot more concentrated, because most of our country just can’t support big cities. And we have far fewer states, which might play into it. It’s also illegal not to vote in my country, which solves a lot of “getting people to vote” problems – and it doesn’t sound like that’s the case in the US.