These checklists are intended as a starting point for the beginning piano technician. There are MANY different and correct ways of learning the skills needed to be a piano technician. This is only one suggested method.
For many of the tasks, you will need assistance of a mentor before you can check it off. Ideally, you would meet up with a mentor and he or she would show you the task, allow you to practice it, and then initial it off of your list. It is up to you to continue practicing the skill to mastery.