Can you explain the BRRRR method to a beginner?

Buy a run-down rental below what it will be worth fixed up. Renovate it. Rent it out. Then refinance into a normal mortgage based on the new, higher value. If you bought cheaply enough, the refinance pays back the cash you spent, and you own a rental with little of your own money in it.

A house that needs work sells for $150,000. Fixed up, similar houses sell for $260,000. You buy it mostly with a short-term loan and spend $40,000 on the renovation. About $71,000 of the project is your cash.

You lease it for $2,300 a month. A bank appraises it at $260,000 and lends 75%, $195,000. That pays off the short-term loan and hands you about $54,000. You now own a $260,000 rental with $65,000 of equity, a tenant, and about $17,000 of your money still in it. The $54,000 funds the next house.