The easiest way to navigate Google Maps is by using drag-and-drop techniques. To accomplish this, you to move the mouse cursor to an area of the map, hold down the left mouse button, and while keeping the mouse button held down, move the mouse cursor in the direction opposite of what you want to show on the map.
For example, if you want to the map to move south, you would hold down the mouse button and move the mouse up. This will drag the mouth northwards, thus revealing more of the map to the south.
If the area you would like centered on the map is currently being displayed, perhaps towards the edge of the map, you can do two things to center it. You can click on the area, hold down the left mouse button, and drag it toward the center. Or, you can double-click on the area. This will not only center that area of the map, but also zoom in one notch.
To zoom in and out with the mouse, you can use the mouse wheel between the two mouse buttons. Moving the wheel forward will zoom in, and moving it backward will zoom out. If you do not have a mouse wheel on your mouse, you can zoom in and out using the navigation icons on the left side of Google Maps.
