Do It (Tomorrow) is based on a simple concept where you can just look at what you have to do today and push less important things to later.
The "days" aren't literal dates, add todos to today - they will stay on that page forever until you cross them off or delete them. The pages are more like 'now' and 'later', at least that's how I use it.
Yeah the way I do it I have two todo lists- one for Today, and one for This Week. Each night I move stuff from my This Week list into my Today list to be done the next day. That's how I will use this.