There isn't really much to "get" about Blair right now, she's only just been introduced.
That being said, she feels like a foil to the MC, coming from a world where magic doesn't exist as the others recognise it, but more of a lean on technology, like the MC's world.
But where the MC once had to explain technology to the other girls, they're having to explain magic to someone for whom magic is an impossibility. Or it might be more accurate to say that the girls are now in the MC's shoes, having to explain magic, mana and etherwalking to someone who is a complete sceptic.
Actually, you can understand where Blair's frustration comes from when she repeatedly asks for an explanation and she just gets "its magic" or "its just how we do it" as responses. And Caitlyn certainly didn't help by going into complex theories that went over Blair's head (note that Blair isn't stupid, she's quite intelligent and observant, but Caitlyn made the mistake of not starting from the basics. Because I guarantee, from Blair's perspective, Caitlyn was just spouting nonsensical nonsense to make herself sound smarter and to ridicule Blair).
To be honest, most of the girls didn't help that much either, save for Rae. Its kind of refreshing really, because each of the other girls are so used to magic in their lives that they are able to wrap their heads around the concept of etherwalking and they're being trapped in the rift, but having to explain that to someone like Blair, who has no experience with magic, it's something outside the wheelhouse of everyone involved, except the MC and that's simply because he's gone through this by himself, with some help with Rae.