Open your Excel workbook and select the data you want to include in the chart.

Click on the Insert tab in the ribbon.

In the Charts group, select the type of chart you want to create (e.g., Line, Column, etc.).

Once the chart is created, right-click on the data series you want to plot on a secondary axis.

Select Format Data Series from the context menu.

In the Format Data Series pane, click on the Series Options icon (resembles a bar chart).

Select the option for Secondary Axis under Plot Series On.

Close the Format Data Series pane to apply the changes.

To adjust the chart type for better visualization, right-click the chart and select Change Chart Type.

In the Change Chart Type window, choose Combo Chart from the left panel.

Assign the desired chart type for each data series and ensure the Secondary Axis checkbox is selected for the appropriate series.

Click OK to finalize the changes.