To change the symbol of a chart, simply click into your chart and start typing. This will bring up the Change Symbol field.
To move back in history on your chart, use the scrollwheel of your mouse or the left and right arrow keys on your keyboard.
To zoom in and out of your chart, press the contol key on your keyboard while using the scrollwheel of your mouse, or alternatively the left and right arrow keys of your keyboard.
Many of the chart features are located in the Properties dropdown of the right-click Menu.