Hi there, you just have to begin by entering an accredited nursing program.
You should research community colleges and universities in your state of residence (or state you plan to relocate to), if in the US. For nursing programs (RN or BSN), you can check said state's Board of Nursing (BON) website for a list of accredited programs.
After which, you'll want to find the 'nursing' section within the educational institution of your choosing and review the admissions requirements. Take some time to reflect on where you stand (I.e how many courses you may have completed previously, did any courses expire, etc). Finally, make an appointment with an admissions counselor to further assist you with questions you may have, that are specific to your program of interest.