You get between $15k-$500k up front, and in exchange, the Home IPO company buys a stake in your home.
(They think your home's value will increase, so it's a good deal for them.)
There are no monthly payments because it's not a traditional loan.
You just sold part of your house to the home IPO company.
You can use the money however you'd like.
Or, if you'd rather, you can buy the company out of their investment (you typically can do this at any time).