Considering a 24 unit multi

[Josh James]

How does this deal look?

This is a two story, 2 building multi. On site laundry facility, water is paid by owner, tenant pays electric, no gas, no pool, very good neighborhood, units are in decent shape. There are 8 1 bedroom units, and 16 two bedroom units. Rents range from $400/mo to $550/mo, taxes are $9800/yr, insurance I have no idea, Seller is asking $700k. 

I talked with a Realtor about getting the financials, and she said I needed to write an offer contract, and request them in the option period. That sounds kinda backwards to me? How can I make an offer if I do not know the occupancy, annual maintenance,  and other expenses? I will have no idea how much money I will be making or losing? Am I off the mark here, and the Realtor is right? I have not bought a multi before, so I am charting new territory.

Any advice would be appreciated, thanks!