The pdf directions reference a javascript file. Something like wagmp_map_1.js, but now I believe it is a php file like wagmp_map_1.php. Anyway, it's the same steps.
Look for this in that file map.addOverlay.
The last time I did it, I found 4.
So
map.addOverlay(marker_0);
becomes
map.addOverlay(marker_0);
map.setZoom(6);
The "6" above is the zoom level I used here but it could anything from 0-17.
TroyD