If you want to be a Green Beret, you must pass first the Special Forces Assessment and Selection Course (SFAS). This course requires a minimum score of 260 in the basic physical fitness for the 17-to-21 age group. After completing SFAS, you will be selected by the Army SF instructors to attend the Special Forces Qualification Course (SFQC) that can last from 6 months to a year depending on your occupational specialty. Stew Smith has listed down routines to help you prepare for the Green Beret Training.
Source: https://www.military.com/military-fitness/army-special-operations/army-green-beret-training