Welcome and all. Congrats on finding someone that you really connect with. I know it can be difficult to do. I can empathize with being nervous to meet the OSO. It's intimidating and that relationship plays a big role in the larger scheme of things. Keep in mind, though, you don't have to be her best friend in the world. Start at polite, kind and respectful. You can go from there. And please, before any of you consider moving in with the other. Move to the same town first. Live in a different house. I've heard that is a much better way to transition. In the meantime, good luck in two weeks. I'm sure that will help to give you a clearer picture of his life. Have you been in any poly relationships before? Do you identify as poly yourself?
There are plenty of nuts and bolts threads on here when you perform simple searches. So many great resources to take advantage of. Also, you may or may not have heard of it but there's a great Poly podcast that I love called Polyamory Weekly. It has a variety of topics and I found it very reassuring when I first started listening to it.