For this purpose, Excel lets you add a series of data to a chart and plot it on a second y-axis. A simple chart consists of an x-axis and a y-axis, with the x-axis representing the various rows or ...

Click anywhere on the second chart to select the chart. Press "Ctrl" and "V" to paste the copied data to this chart. Excel will add all of the data series from the first chart into the second one.

10 steps to adding a ... select a single data point; it doesn’t matter which one. The hard part is selecting just one. When you click any data point, Excel selects the full series.