A “Plan” is your scheduled plan for when you will complete something. You can give a plan to a Task, Heading, or List.
By default, Lists that are given a Plan for a future date are hidden from the top-level of your Launchpad into an “Upcoming Lists” section at the bottom. This is to maintain the goal of the Launchpad to show you a list of stuff that’s currently relevant to your life on a daily basis.
You can also add a Time to a Plan to track not just a day, but also a specific time at which it must be completed. If you’ve turned on Notifications in your Settings in Stuff, you’ll receive a notification to your device at the time set aside to accomplish your task.
Whereas a Plan is your personal goal for when you plan to do something, you can use a Deadline to keep track of when it must be completed.
For example, imagine you have an essay that must be turned in by next Friday. You might set the Deadline for next Friday, but the Plan for sometime this weekend - helping you track the difference between when you plan to actually write the essay, in contrast to when it must actually be completed.