When you first use the program, there will be a default list of fields for importing. The Ingredient fields include codes, names, keys, weight, cost, etc. The Nutrients fields include all available nutrients. The Allergens fields includes any allergens associated with the document you're importing.
You can edit the list of import fields here.
In the left (Fields List) pane, Double-click on the item to add it to the the Selected Fields.
Use your mouse to arrange items in the right pane by dragging them up and down (Selected Fields).
Click OK. These fields will now be included in your import.