1. He's saying that at any time he can declare that the US is being invaded and send any non-citizen to a prison in a third country, and there can be no judicial review.

2. Separately, he's saying that he can deport any non-citizen who poses a threat to national security without judicial review.

3. He and his allies are saying that people who do things he doesn't like are committing crimes. For instance, if they don't like a particular government program they call it fraud. If a judge rules against them, they call for the judge's impeachment.

4. He's saying that he can drive any law firm that opposes him out of business by limiting their access to government officials and government contracts. This would mean that any law firm would have to take a huge risk to represent an unpopular client.

So if you take all of this together, if you're a non-citizen, the President, who has absolutely no compunction about falsely accusing people of crimes, is saying that he can accuse you of being a criminal or a national security threat and send you to a prison in El Salvador. He's saying that the courts cannot review his actions, and even if they could, he can drive the lawyers who might represent you out of business.