We started out self managing, and continued as we scaled.

Here is some information that might be helpful.Rent Collection/Property Management:For collecting rent from multiple tenants and managing your property, here are a few popular options:Cozy.co: This platform is free for landlords and provides rent collection, expense tracking, and even maintenance request functionalities.Buildium: This is more comprehensive and suitable if you ever decide to scale up and manage multiple properties.

Moreover, there are leasing companies such as PadSplit and HomeRoom who implement this daily, but for your property size/scale, I don't believe they'll be necessary. 

With some experience I’d like to take on more rentals and scale up to multi family.

-How to scale your business.

A word of caution on "up and comming" in Milwaukee and put that on a time scale.

Depending on the degree you want to scale.  

@Jide Alufa scale quicker with multi-family!

With that type of starting capital, you'll have some space to scale 'relatively' quickly, but start with one, maybe two, and familiarize yourself with turnaround times and payment/draw schedules as you go. 

If your tenants stop paying it's likely your house value will be dropping too, this comes in unison and at a grand scale.