I am a registered nurse in Mongolia and would like to work in USA as a RN?

I found out that I need to take NCLEX. But I don't know how to apply for this exam and where to take it? do i have to go to America in order to take it? Also, Do i have to get certain permission to take this exam? Is there any websites or professionals who can advise me on this. Please, send me an email. Thank you for your time and attention