Having a background in finance from Harvard Extension helps. I'll start working on my MBA. from Yale Executive after I earn my UTP slot.
The investment theory really just focuses upon your available equity, credit, location, and risk:reward ratio you feel comfortable with.
If you are just getting started and are probably in your 20's & 30's. Its easy, just live where you can rent (like a 4-plex), buy a tesla instead of a Lamborghini, and ideally marry a beutiful women who works.
As for the rest, that's more corporate style investing. And nobody without a formal education should attempt that.
As real estate, oil, securities, and business development have a much higher ROI.