1. Select the image
2. Once the image is selected click on the Image Map Editor

1. Select the shape required and select New Area
2. Select the new area to move it to the required position and use the small red box to re size the area
3. Enter in the required details, including the URL, the target, and enter a comment if required
4. Once you are happy with all the settings click on Update Area

If you to update the area select the mapping, make the changes and click update area.  If you want to add another area, select New Area and follow steps 1-4.  To remove an area select it and clink on remove area, or alternatively remove all to remove all the current mappings on this image.