Great question. People moving their own homes in is what we call organic move ins. There are a small number of markets that this is common but you should expect to bring homes in (new or used), set them up, and sell them like a builder would in a development. They then pay you lot rent every month.
The alternative strategy is a home rental model which is like running an apartment building which means you have turnover, a lot of make-ready costs, etc.
You can buy the park and assuming the market is conducive for the lot rent model, you can fix the homes and sell them. I’d recommend the sales/lot rent model.
Unless you’re in a very strong market that has such strong demand that people are buying homes and moving them In Organically then your bringing the homes in yourself.
Check out my profile for a bunch of good resources for mobile home park investing and as always bigger pockets is a great resource. Hope this helps.