Sounds like a big fat mess! 

Yes, there's broke college girls on there looking for a guy to pay her regularly, but, there are also business women, doctors, etc, who also realize the need to trim the fat.

@Jillian Sidoti or Gene Trowbridge.

Lost 8 pounds of fat and only 1 pound of lean body mass in the process.

I'd start with two of David Lindahl's books, Gene Trowbridge book.

Here is a book list for you:"Buying and Selling Apartment Buildings" by Steve Burges"Multifamily Millions" by Dave Lindahl"It's a While New Business" by Gene Trowbridge "How to Create Lifetime Cashflow by Buying Multifamily Properties" by Rod Khelif.To answer your question, LOI is your first step.

Or maybe after a few years you decide one or two are just your "problem child" and you want to sell them to reduce your headaches by trimming the fat. 

Originally posted by @Gene Chandler:It is really an interesting business and doable if you have the time and understand each State and County's rules.

@Gene Hacker can get you more information if you can make it

Gene Trowbridge has a great book called ”It’s a Whole New Business” which is very educational.