From an early age, Abraham, originally born Abram, questioned the faith he was taught by his father. Abraham came to believe differently from his father; Abraham believed that the world as we know it was the work of one Creator, and with this new found belief, Abraham taught his beliefs to others. Eventually, this one Creator that Abraham believed in, came to him and made a covenant with him. Abraham was to leave his family to preach, and in return he would be provided with a great nation. Abraham did as asked, and this covenant between him and God is very traditional to Judaism. The covenant basically states that God has certain obligations to us, and we have certain obligations to Him. In order to prove Abraham's worthiness of the covenant, he was subjected to ten tests of faith. He passed all ten tests, and was proved worthy.
Through Abraham's son Jacob, who was later named Israel, Jewish people were later known as Children of Israel which showed them as being decedents of Abraham. Time passed, and the children of Israel became slaves in Egypt, but were eventually led out by Moses. Moses brought them out of Israel and led them to Mount Sinai where God revealed himself to them and offered them a covenant. God revealed the Torah to the people, and all responded with open arms.
The Torah explains all Jewish laws, teachings, and beliefs. The Torah is basically the Old Testament consisting of the five books of Moses: Genesis, Exodus, Leviticus, Numbers and Deuteronomy. Other important pieces of Jewish literature include the Talmud, which explains what scriptures mean and how to interpret them, as well as midrashim, which are stories that expand on those in the Bible and show how Jewish law is received from them, and help to teach moral lessons. The Torah helps to explain what Jewish beliefs are, but even more helpful is Rambam's thirteen principles of faith. .
Rambam's thirteen principles of faith are very simple, and are widely accepted as Jewish belief.