This is what I can tell you from what I've seen so far.
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Spencer Carlin: Best friends with Ashley/likes Aiden/doesn't know if she likes girls or not
Ashley Davies: Spencer's best friend/has given up on boys/wants Spencer
Clay Carlin: Spencer's brother/adopted/is a virgin/likes Chelsea
Glen Carlin: Spencer's other brother/not adopted/dates Madison/on the basketball team
Aiden Dennison: Likes Spencer/use to be Madison's boyfriend/also on the basketball team
Madison Duarte: Ashley's worst enemy/dates Glen/on the cheerleading squad
Sean Miller: Seen as the bad boy type/really smart/helps Clay get around at school
Chelsea: likes Clay/smart
This is how it happened. Spencer and her family moved from Ohio (or Utah?) to Los Angeles, and on Spencer's first day she meets Ashley who gives her attitude at first glance but later on they become friends. One day at Ashley's house, she admits to being attracted to girls and ends up holding Spencer's hand in the process. On that same day, Spencer sees Aiden who she becomes attracted to but realizes that he dates the cheerleading captain, Madison. That's when Glen comes in and tries out for the basketball team and he ultimately becomes better than Aiden and that makes Madison notice him. Aiden on the other hand is already getting into Spencer and he and Madison obviously break up and go their separate ways. Aiden liking Spencer, Glen dating Madison. Clay is the smart one in the family and because he was adopted, he believes he must live up to that. One day, he meets Sean who he has some problems with at first but eventually they become friends because Sean teaches him how he needs to be to make it at their school. Then, he meets Chelsea who's the cute girl that he likes. The bad part is there is another boy who likes Chelsea and since she doesn't like him (but likes Clay), he decides to beat Clay up one day. In the end, Clay and Chelsea get together.
On the next episode, Spencer is going to find out if she also prefers girls.
That about sums it up, I believe.