The person asking does not appear to understand the basics, so it calls for a basic response.

When I started out many years ago I was living in a basement apartment with no furniture.

It used to be a 2 story house with basement, but got built out into 2 units on each floor, a basement unit, and a backyard unit.

As we rent in a solid C class market, I use the 3x as a basement level criteria.

If it localize, i.e. a roof leak in a certain area, a wall in a basement that have moisture coming through.

Or build 2 skinny houses, each with a basement suite and a garage/laneway suite.

That said, here is a basic outline of what I teach in Texas that is directly applicable to the question at hand.

I had a deal fall through with a buyer client of mine for an HPR with a basement unit after schlepping to the deed office to look through HPR docs, only to find a restriction on more than two unrelated adults living in the property.

He owns thousands if front doors and has been teaching and mentoring for 25 years.I am a basic $500.00 member and just renewed at the $295.00 special and am eligible to travel to Houston and take the two day workshop with Del Walmsley anytime again.  

Even the high-priced gurus give you a basic introduction for free, or low cost.Look into Brad Sumrok.