No realtor, first house hack?

[Avery Robertson]

I am wondering if I need to get a realtor involved or what should be my next steps in buying my first duplex to house hack? 

I sent a letter to a duplex owner of a property my wife and I liked. The owner called and said he'd be interested in selling later this month. I've never bought real estate and I've only looked at doing it through traditional realtor listed and realtor purchased. 

Do I need to get a realtor involved even though I started all the leg work? If not what should my next steps be after I look at the property later this month?