Audiovox CDM-9900

They are probably referring to the Scheduler (page 127 of your User Manual). You could also record Voice Notes to yourself (page 124).

There is kind of a to-do list. If you go to the scheduler, and then go to options and then go to "All Events" it lists everything in your calendar. Not exactly a to-do list, but depending on what you want to use it for, it's close