What is the process of buying a property through a private sale?

[Eric Hathway]

I am talking to the owner of a 5 unit building I am considering purchasing from him. It is not listed on the MLS. How would I submit an offer? Is there a standard format? Would there be a deposit and escrow? Should I use my real estate agent to make things run smoothly? What if the owner doesn't want to pay an agent's commission?

I'm sure it can be done, but I don't want to make a mistake like using a contract that exposes me. 

Thank you