Answer:
First, the President must nominate someone to become a Justice on the United States Supreme Court when there is a vacancy. Then, the Senate must confirm the nomination with a majority vote.
Step-by-step explanation:
There are no qualifications listed by the Constitution for becoming a Justice. The only steps one has to go through is the nomination and Senate confirmation.
However, in practice, having experience in law is a requirement as all previous Justices have been trained in law, even if they didn't go to law school.