Finally, beginning with the introductory lesson (the Hundred), each succeeding exercise should be mastered before proceeding progressively with the following exercise. Make a close study of each exercise and do not attempt any other exercise until you have first mastered the current one and know its routine down to the last detail without any reference to the text. Be certain you have your entire body under complete mental control.
Even though I believe that it’s beneficial to work towards mastering all the exercises simultaneously, I agree that mastering the Hundred will provide considerable benefits to you. Start with 20 and progress by 5’s until you reach 100. It’s quite simple actually.