They have no plan. We know this because it's already mathematically impossible to do what they're wanting to do. There literally aren't enough places to detain all the immigrants they want to deport, nor are there enough ICE employees to even process them. You can't just snatch people up and stuff 'em on an airplane and be done with it, there's a whole process involved that our system does not have the capacity to even begin to support.
Don't get me wrong, they're 100% going to do some deportations, and they'll make sure that it's national news when they do it. They'll make sure that FOX tells you about their criminal histories, and they'll make sure CNN tells you about their children locked in cages hundreds of miles away from their parents.
It's not about actually deporting immigrants. It's about making the immigrants that are already here feel unsafe. It's about making them feel insecure, worrying about whether they'll be eating dinner tomorrow at home, or behind bars. It's about making everybody live in fear; citizens are to fear their criminal neighbors, and immigrants are to fear the neighbors that would rat them out to ICE. Everything Trump and his team do are about making people turn against each other. And it works.