Position the cursor where you want the ImageMap in your document.
Choose Insert - Picture - From File, select and insert a bitmap picture.
With the picture selected, choose Edit - ImageMap. You see the ImageMap Editor, which displays the picture at the background.
Use the icons in the ImageMap Editor to draw a hotspot shape, for example a rectangle, over the image at the background.
You can see an extended help text on the functions of each icon when you enable Extended Help in Tools - Options - OpenOffice.org - General.
Enter the "Address" URL that will be shown in a Web browser when the user clicks the hotspot.
Optionally, enter the "Text" that will be shown as a tip when the user points the mouse to the hotspot.
Click the Apply button to apply your changes, and close the ImageMap Editor.
Save the document in the OpenOffice.org or HTML format.
You may save the ImageMap as a file and upload that file to a Web server, for example.