Adding a Google Map via a plugin
I highly recommend installing WP Google Maps, or a Google Maps plugin of your choice. Google Maps has a lot of capabilities, using a plugin makes it easy to use.
You can also generate a map through one of the many online Google Maps generators such as
In any event, once you have your map ready, just add it in the Custom Content setting in the ShiftNav Control Panel.
WP Google Maps
After installing the plugin go to Maps > Maps to create your map. Then copy the generated shortcode into Appearance > ShiftNav > Main ShiftNav Settings and paste the shortcode into either of the Custom Content areas.