I've thought of a few more things, that you might want to know about polyamory. A lot of this is just vocabulary, but it comes with some thoughts and concepts, about what polyamory is and how it works.
First is the word "polycule." It refers to all the individuals in one's polyamorous network, and how each one is linked to the whole. The simplest kinds of polycule are, a V and a triad. A V is where one person -- a hinge -- is romantically involved with two other people -- the legs. The "leg people" are only platonically connected to each other -- and sometimes they have no contact with each other. A triad is a group of three people where each pair of people -- each dyad -- are romantically connected with each other.
And then there are somewhat more complex polycules, such as the N (two V's) and the quad (an interconnected group of four people). Finally, there can be super complex polycules composed of all kinds of interconnected cells and zigzags, all linked together in one huge -- well, polycule. Some links could be platonic, and others could be romantic. And of course there are polycules that are in between on the scale of complexity. No two polycules are quite the same.
Some polycules are open, and some are closed. A closed polycule is when no new people will be joining the polycule, it is strictly limited to the people already in it. My polycule is a closed V: It might be conceivable that someone new could join our V (making it an N), but realistically, that will probably never happen. My V is also polyfidelitous. Polyfidelity (poly-fi for short) is when you have three or more people in a romantic network, but none of those three (or more) people will have sex (or romance) with anyone outside the network (outside the polycule). In my V, the two men only have sex with the one woman -- the hinge. And she only has sex with us. Polyfidelity.
Finally, I don't think I mentioned "compersion." Compersion, in a word, is the opposite of jealousy. It is when your partner is with someone other than you, having sex and/or romance with that other someone, and instead of being jealous (of your partner and the other someone), you are happy for your partner, and glad s/he is having a good time. Compersion. Compersion is not required, for poly to be successful. It is just a nice perk when it happens. The only thing you need for successful poly is, healthy management of your jealousy.