Phoca Maps is a Joomla! component. It is a small component which displays Google Maps on your site. This component doesn't include too much of parameters, the idea of using this component is a fast creation of map on your site.
Just set Google Maps API key in Parameters, go to Extensions - Maps - New, click on Coordinates button, then click on the place in the map you want to display and save it. Finally create menu link to this map.
If you need to set a marker or more markers, just go to Extensions - Markers - New, select map, click on Coordinates button, then click on the place in the map you want the marker will be set. Add description (you can include images too) and save it. Marker will be displayed in the map.