$5 million dollar portfolio

[Abou C.]

Hello

Goal: 

My business partner and I are starting our first RE investment company next year, in Boston,MA. We just completed our real estate sale class, which was the best investment we made dusk. 

Plan:

Start RE investment company solely focused on  "multifamily/commercial + development". Long term goal to turn this company into a Private equity firm in Boston, Ma focus on a niche or selected market with added value.  

Question?

What is the process or how does one build a $5 million dollar + portfolio in five years or shorter?.  How many units must we hold assuming all profitable after expenses, as well as how many or what type of commercial property? i.e. strip mall, retail place etc.