Assuming I had a compliant congress, I would eliminate every (non-military/non-judicial) federal agency that was not specifically referenced in the constitution.
I would also repeal every law that empowers the federal government to surveil its own people.
I would also root out and prosecute bribery, extortion and blackmail everywhere it existed within the federal bureaucracy, both current and past.
I would also pass a law mandating all federal elections be conducted with paper ballots and hand-counting while being recorded on video.
I would also build an electrified wall everywhere the USA had a ground-border with another nation.
I would also ... uhhhhhhhhhh, ya know what, just watch the video.