To plot one set of data against another in Microsoft Excel, you can use the "scatter plot" chart type. Here's how to do it:

1. Enter your data into two columns, with the x-axis values in one column and the y-axis values in another column.
2. Select both columns of data.
3. Click on the "Insert" tab in the ribbon at the top of the Excel window.
4. Click on the "Scatter" chart type in the "Charts" section.
5. Choose the chart subtype that you prefer. The default subtype is usually fine.
6. Excel will create a scatter plot with your data. If you want to add labels or change the formatting of the chart, you can use the "Chart Tools" section of the ribbon that appears when you click on the chart.
7. If you want to add a trendline to the chart, right-click on one of the data points and choose "Add Trendline" from the context menu. You can choose the type of trendline you want and customize its appearance and options.

That's it! You should now have a scatter plot that shows one set of data plotted against another, with a single line connecting the points.