Lease Options for wholesalers

[Michael Fagan]

I was reading an article, and it all made sense and was easy to follow except when I got to this:

"Usually in 2 weeks I get a buyer, and we make $5000 a house (sometimes I take a note on maybe 20% to 33% of the down payment.) "...

How are you making $5000 on the house, does taking a note mean borrowing the buyer the down payment?

"This is in and out, not a sandwich lease option." ... 

I'm thinking that means once the transaction is done they are done?

"We act as a principal in a lease option, then assign. We work with land contracts too in the same manner."...

Not sure what acting as the principal means or assigning?

I have a ton of questions about how the mortgage companies are involved, and how the wholesaler would get paid? I sounds like basically the wholesaler would be the middleman to the transaction, but the buyer has to get the mortgage before the seller would be free of his mortgage and I believe in a rent to own situation could take quite a while.