This question is not clear. My best guess would be to say that the values of a data series are represenations of the individual data items in the series.
It would be a group of cells in Excel that have values in them. These can then be identified for use in creating charts in Excel. Different charts need data series for them to show.
You can assign a numerical value to each element in your data series. There are several ways to do that. Here is a simple example: In cell A1 enter your first data element. Let that entry be GREEN....