Turning a SFH into a duplex - newbie here

[James Phillips]

I found a property! Needs to be brought up to code, but its advertised as a SFH when it was clearly a duplex. I'd like to buy it, turn it into a duplex, rent it out and sell it or (if the tenants are great) keep it a while.

Does anyone have experience with that kind of flip?  Anything I need to watch out for or to anticipate?  This may be too difficult for a newbie to start out on