I'd be happy to answer any questions you have with the caveat that they would only represent one poly-bi-girl's personal view. You can read about how I started on my Journey to Poly in my blog.
My initial poly-type values come from reading Heinlein from an early age. Other people come too poly through pagan or spiritual beliefs. Others fall into poly due to circumstance. Some come from the swinging side of things. There are many roads to poly and no two are exactly the same. The poly that they practice will be unique to the people involved.
Me: poly bi female, in an "open-but-not-looking" Vee-plus with -
MrS: hetero polyflexible male, live-in husband (21+ yrs)
Dude: hetero poly male, live-in boyfriend (3+ yrs) and MrS's best friend
Lotus: poly bi female, "it's complicated" relationships with Dude/JaneQ/MrS (1+ years)
TT: poly male, married to Lotus, FB with JaneQ
VV and MsJ: bi-women with male primaries, LTR LDR FWBs to JaneQ
My poly blogs here:
The Journey of JaneQSmythe
The Notebook of JaneQSmythe