The easiest way to create a custom KML is using Google’s “My Maps” feature. Assuming you already have a MyMaps created, you can use it with this plugin by following these steps:
Grab the KML of your My Map
Go to your My Maps page, and select the map you want to use. Then, click on the “edit” button as shown below:
A link to Google Earth should now appear above the map. Right click on the link, and copy the link.
Add the KML to the shortcode
Now add that link to the shortcode like this:
[ map w="500" h="400" maptype="SATELLITE" kml="http://maps.google.com/maps/ms?ie=UTF8&hl=en&vps=2&jsv=295c&msa=0&output=nl&msid=106943900362299320636.00047ede6cd99f793ce99" ]