Welcome MusicalRose! I'm sure you'll find lots of great info and awesome people to help you out with questions.
If you and your significant other are open and honest with each other and anyone else that you may bring in to your relationship then this journey will be a touch easier. Notice I said touch, because there's nothing easy about being in a poly-amorous relationship, but if done right the rewards are tremendous.
Have fun looking around and make lots of friends!!