Image URL: Type in the URL of the image / artwork that represents your podcast in this field. iTunes prefers 300 x 300 square shaped .jpg images, although it also supports .png format.
Subtitle: Type in the Subtitle of your podcast in this field. It is displayed in the Description column in iTunes and it is recommended to limit it to only a few words for best display.
Summary: Fill in a summary of your podcast in this field in upto 4000 characters.
Keywords: Type in a maximum of 12 comma seperated keywords that you think people might use to search a podcast like yours. Keep them as relevent to your podcast topic as possible.
Author Name: Type in the author's name in this field. This is shown in the Artist column in iTunes.
Author Email: Type in the author's email address in this field.
Category: Select a category that your podcast falls in from this pull down menu to reveal its subcategories in the "Sub Category" multiple selection box under it. Then select the subcategories (hold ctrl and click for multiple selection) that are revelent to your podcast from "Sub Category" box and click the "Add>>" button to add these sub categories to the "Your Selection" box.
All the categories present in the "Your Selection" box will be added to your feed once the "Save Changes" button is clicked.
If you wish to remove any of the selected categories, simply select the ones you want to remove from the "Your Selection" box and click the "<<Remove" button.