@jjl618 You apply to the college and select the nursing program on the application! Sometimes you can get accepted into the school itself but not the nursing program because of the wait list or certain requirements.. so at that point you could enroll into your college classes and work on your pre-requisites until a spot opens up.
I applied to two nursing programs but I wasn't 100% sure what I wanted to major in at the time so I applied to other schools as undecided. One school said my SAT scores weren't high enough for their nursing program, and the other accepted me. So I was in the BSN program the fall after graduating high school. I now realize how lucky I was!