Buying a duplex with current owner as occupant

[Bily Elliott]

I have found a duplex for sale that was purchased from a bank in Oct of 2013 (I saw the listing when it was for sale thru the bank, but was not in a position to buy so I didn't look at the property), the current owners did some rehabs (according to the listing), renovated the top floor and live there and have done MOST of the work in the bottom unit.  Obviously the current owners are not paying rent, am I right in thinking there are multiple steps to take in making an offer?  Obviously an offer would need to be accepted, but if they are wanting to stay they would also have to agree to rental terms and rate and such right?  Would all of that need to be submitted at one time, an offer and a rental agreement.  I wouldn't want to run a background check and such on a property I don't own, or would it be similar to inheriting a tenant even though they are not paying and assume they are a month to month lease and try to get into a 12 month agreement?