On the
Tools tab, in the Templates
group, click Map Styles. 
You can use the Template Organizer's Style Templates tab to manage your style templates.
On the
Tools tab, in the Templates
group, click Map Styles.
The list shows all the available collections and the style templates they contain. You can add or remove entire collections from the Organizer using the Package folders option. To further organize your styles, you may create folders within the collections.
Click the commands under Folder Commands to create a new folder, rename a folder, or delete a folder.
Delete and Rename apply to entire folders. If you delete a folder, all the templates it contains will also be deleted.
Move styles by dragging to a new folder or collection.
To modify, duplicate, delete or rename a style, select it in the list, and then use the Template Commands.
