Real Estate Business Purchase- Owner Finance

[Doug Pham]

Hello All, a good friend who I have know for over 20 years  is retiring from his real estate residential construction and remodeling company operating successfully for over 20 years. We have discussed my interest in taking over the business through an owner finance. 

What are some legal advisors and processes that I should take to ensure all the proper documents are in place to protect both party? Any help is appreciated. 

Thanks

Doug