I don't know anything about how girls get a guy there was this cute girl in my grade who I started liking right before valentines, I asked her out, she said yeah, and it was good. turned out she liked me alot, and she was smart and really hot, so it was there.
I geuss girls don't ask guys out, girls try to get them to ask you out. that is the most annoying thing ever. cus i had to geuss, and help my bros out, and wingman the hell out of a few situations.
If hes taken, he's taken. but couples break up all the time. You like him, get in his good books. Flirt around, let him know you like him. he likes you back, he'll show you. when they break up, don't wait. sounds like you arent the only one who likes him. try to single him out, get him away, and ask him out. to like the movies. if he shows you he's not intrested, don't worry, theirs other guys on the planet