How exactly do investors earn money

[Rasheed Mcdaniel]

Hello I live in Philadelphia, PA. I am new to the real estate world and for my first deal I plan to obtain a owner occupied duplex and build my buy and hold portfolio from there. 

My first deal will be funded by fha loan but I actually have a family friend that is in the business already. I am interested in approaching him for a partnership on my second property (which I know maybe I'm jumping the gun a bit, but I just would like to get my info together now) 

Basically I don't understand quite how to present to him it being a good investment. If we find a great property that cash flows $100 per door (let's say on duplex) does he only make the  $100 ($200 split two ways) or does he get that plus equity split or how does that work? 

P.s. This is my first post so please excuse if it's out of context in anyway