By default, Excel will use the first column for the X coordinate and the second for the Y coordinate. To add additional data for the Y axis, you need corresponding data for the X axis as well.

This article explains how to add a secondary axis to a chart in Excel so you can view unlike categories on the same graph. These instructions work in Excel in Microsoft 365, Excel 2021, Excel 2019 ...

Naming Basics Best practice recommendations are to create a chart placing independent variables on the horizontal, x-axis and dependent variables on the vertical, y-axis.

If you have uneven distribution of data in your Excel chart, here is a better way to change the automatic axis settings.