Buying house directly from home owner

[Mel Saffold]

Hey guys, I have a preapproval from the bank for purchase and rehab a property for up to 170k. There is a non MLS listed property that a owner I know is willing to sell. I'm relatively new to real estate and I wanted to know if this type of transaction is simple as getting a purchase sale contract going with the seller and forwarding it over to the attorney and lender? What type of due diligence should I be doing? Do's? Don't? How to properly go about this? Thanks a lot! - Mel