Charts are interactive. Here is an overview what you can do with a chart.
When you hover the lines or bars on the chart you will see a tooltip with exact value.
When you hover the chart area the cursor changes into a crosshair. Hold and drag to zoom in a particular area of the chart.
To zoom out double-click anywhere in the chart area.
To exclude or include particular series click on its name in the legend area.
To exclude or include all series except one double-click on its name in the legend area.