You can use the Property inspector to assign URLs, alternate text, targets, and custom names to hotspots. If the Property inspector is minimized, click the expander arrow in the lower-right corner to see all properties.

This is a picture of the feature being described.

You assign hotspot properties the same way you assign slice properties. For more information on using the Property inspector to assign URLs, alt text, target frames, and custom names, see Preparing slices for export.