To change map zoom, first enter the map widget's edit mode. Drag and drop the map widget into any zone on your site. Hover over the widget and click on the pencil icon to edit it. Finally, drag the zoom bar to the left or right until you get your desired zoom.
Each map widget shows a map in a certain scale. The map can show either continents, countries, states or streets - it all depends on the zoom you set for it. The amount of zoom you use generally depends on what you want to show on your map. If you want to show the location of your business for example - you would most likely choose a higher zoom to show where the street is located.