There are four main windows in Mangia!  Each has its own Help window:

The Recipe Browser window list all the recipes from files you select. The list is divided into Categories; clicking on one of the tabs brings that Category and its recipes to the front of the box. You can also narrow the list down to different kinds of recipes by clicking on Match What...

The Recipe Clipboard window contains a list of recipes that you’ve set aside for later; usually these are a set of recipes you are planning to fix. Here recipes can be grouped into meals with descriptive comments, scaled, and edited.

The Pantry window shows you a list of ingredients that Mangia!  thinks you have around the house. You can add or delete any ingredients in this window.

The Shopping List window shows the ingredients from recipes you select and lets you edit the list (by adding or deleting items) to reflect the ingredients you actually need.