I was under the impression that Jerusalem existed before the Jewish people arrives there. Is this accurate or was it founded by the Jewish people?
No one knows. The first settlements appear to have been 3,500-4,000 BC.
According to the Bible, it was conquered in about 1000 BC by King David from the Jebusites, and became known as the "City of David" and the capital of his kingdom of Israel.
So, it was first founded by unknown people long before the Jewish religion existed.