Question about continuation pay for Navy

Hello everyone! I’m looking into continuation pay and I’m a little confused about the obligated service. I know you must submit for CP between 8-12 years of service for 4 years but is it saying you agree to serve an extra 4 years AFTER you hit your 12 year mark or an extra 4 years from the time you submitted for CP or your SEAOS? I’m sorry if this question is silly, I’m just so confused and google is not helping