You should leave your money untouched in a CD until the term you’ve chosen ends. Then, you can renew it for the same period of time, choose another CD term or bank altogether or withdraw your funds for something else.
If you don't withdraw your money when the term ends, some CDs are set up to automatically renew, but you might get locked into a lower interest rate. CDs generally offer a grace period of a few days so you can decide to withdraw the money or renew the CD. It’s a good idea to have a plan for your funds once the CD term ends.