The Home screen provides an overview of your day and leads to other important screens - Meals, Exercises, Weight, and the rest.
For weight, you can switch between displaying weight lost and current weight in the Settings application, in the MyNetDiary section.
"Total left" in the Analysis row displays the total calories left based on your plan, which you setup on the Plan page of the web site.
You can return to this screen quickly from any other screen by tapping the Home icon at the bottom left corner of the screen.
You can navigate between dates by tapping the arrows at the top part of the screen. To quickly return to Today's date, tap on the date.