Refinance part of BRRRR

[Scott Stahr]

I'm not understanding the refinance aspect of BRRRR.

In my scenario, I'd like to rent out the house I'm currently living in. The house was a foreclosure and I was able to get it for way under market value. The idea was to utilize the BRRRR methodology to refinance my current house to the appraised value and use the cash to purchase another house. I guess I have two questions:

1. Can the BRRRR methodology work in my scenario or do I need to have a renter in there first?

2.  Say my house is worth 200K and appraises to that value.  When I refinance to the 200k 30 year loan, the bank will give me 150k?  I don't understand this step at all.