Create new HTML page and add a picture.
I have inserted a map of Europe. I will add web links for two different countries.
Now mark part on the map, where you want to add first link.
Under properties select Polygon Hotspot Tool.
Under Properties at Link field enter a web page.
At Target field enter _blank, which means, that the web page will open in new window.
Save the page (Ctrl + S) and press F12 to see your result.
Click the link you have created.