The statement "They enforce the separation of powers between the branches of government" is not a function of the articles of the Constitution.
The articles describe the structure and powers of the three branches of government, but the enforcement of separation of powers relies on the system of checks and balances, which is implemented through the interaction of those branches rather than being explicitly enforced by the articles themselves. The other functions mentioned are indeed covered by the articles of the Constitution: they explain the branches of government, detail the amendment process, and outline the goals of the Constitution.