Hi! I've been through all of this, as I am in a four-year BSN program.
First, you consider the university's general admission requirements (this should be on the website). You apply to the university (not the nursing school).
Second, you meet with a freshman adviser and then
you should ask to meet with the nursing school's adviser. They might say you just need to meet with the freshman adviser, but really
push to meet with the actual nursing school's adviser, or at least an adviser who knows exactly how the nursing school considers applicants.
Third, do really well in your prereqs during your freshman and sophomore years.
Fourth, in your sophomore year apply to the nursing school, making sure that you meet the nursing school's admission requirements. While the university looked at your SAT score and HS transcript, the nursing school will look at your prereq GPA and possibly and entrance exam score.
Fifth, pray you get in.
I'm currently in the fifth category.