I've a question about SAT scores

I just did my first SAT and I don’t feel extremely confident about it (I want to go to an Ivy league, so I’m shooting for the 1500s). I know that Yale requires to see all the scores. If I do badly on this one, how will it affect my application? Like, let’s say I get 1250 and 1480. How do they interpret? Do they do an average or something like that? Or do they really consider just the last one?