With that said, you will need a Residential Property Condition Disclosure. If you get a buyer that is represented by a Realtor they can provide that to you. The actual contract and other required documents will come to you when an offer is made, if it comes from a Realtor. If it is just you and someone who saw your FSBO sign then I suggest you contact a good Real Estate Attorney and they can assist. As for being willing to COOP with a Realtor you should put that on your sign as well.
Give me a call if you have any additional questions and I will try to help, all I ask is that should you decide you want to hire a professional, you will give me a call.
If you need assistance by asking what documents are required to sell your property yourself then perhaps you should consider hiring an experienced local agent to guide and counsel you through the process. Your agent can also provide much more market exposure to attract the largest pool of buyers which is something that can be very costly to you selling yourself. And, it's very likely that a buyer will have agent representation so will put you at a disadvantage.
Just food for thought....