Real Estate Law USA.com

i need a lot of expertise on real estate. my wife and i own and home in michigan, and we have and buyer, but the buy like to go "lease uption to buy." what i like to know what is the rules and the law and what is my responablilty here. but i live in las vegas, please explain, what will you due. yes! i due have and realture that sale my home, but i like to know also what does he get out of it. i need someone who is in realestate law and know what they are doing, please help out with al ot of question and answer, asap, thank you!