The framers of the Constitution felt that the judicial branch was the least important of the branches.  For this reason, they left it for last when writing the Constitution.  The legislative branch is addressed in Article I.  The executive branch is addressed in Article II.  The judicial branch is addressed in Article III.

The Supreme Court itself is created by Article III, Section 1 and Section 2.  Section 1 declares that there will be a supreme court and that there can be inferior courts if the Congress chooses to make them.  It also says how long judges’ terms are.  Section 2 lays out what the Supreme Court’s jurisdiction is.