iBooks Author provides a variety of widgets that make it easy to add interactive objects to your book. Widget types include:
Gallery: A sequence of images your readers can swipe or click through, each with its own custom caption.
Media: A movie or audio file readers can play.
Review: A sequence of interactive multiple-choice or drag-to-target questions.
Keynote: A slideshow or other presentation created with Keynote.
Interactive image: A graphic with callouts (labels); readers can pan and zoom to view detailed information about specific parts of the graphic.
3D: Add a 3D COLLADA (.dae) file readers can manipulate.
Scrolling Sidebar: Content (with text, images, and shapes) that’s related to the surrounding text but isn’t part of the main text flow. In the completed book, readers can scroll through the contents of the sidebar separately from the rest of the page.
Popover: An overlay (with text, images, and shapes) that opens when the reader taps or clicks an image in the completed book.
HTML: An HTML5 widget (with the extension .wdgt).
Note: Not all widgets are available in EPUB templates.
After you add a widget (by choosing one from the Widgets pop-up menu 
in the toolbar), you can customize it using the Widget inspector. The options available in the Widget inspector change depending on the kind of widget currently selected. When you add a widget, the corresponding inspector controls appear.
The following inspector controls are available for most widgets:
Layout: Use the pop-up menu to choose where the label and caption go (above or below the widget).
Title: Select this checkbox to give the widget a title. With a title, you can also use a label, such as Figure or Diagram. These labels are automatically numbered for you throughout the book.
Caption: Select this checkbox to give the widget a caption. In your completed book, readers can scroll captions if all their text isn’t visible.
Background: Select this checkbox to customize the background behind the widget. Drag the Margin slider to change how much of the background appears.
Accessibility Description: Add accessibility descriptions for VoiceOver (the Apple screen reader for those with impaired vision) to read when objects are viewed on iPhone, iPad, or Mac. If you leave this field empty, VoiceOver speaks the object’s default description.
VoiceOver automatically reads text associated with widgets, such as titles, labels, and captions.
You can enable a widget to appear larger when a reader taps or clicks it.