Carry out the following steps to create an opportunity report with a chart that is grouped by the standard field stage:

1. Click on the Reports tab.
2. Click on New Report, as shown in the following screenshot:

3. In the resulting Create New Report page, select the Opportunities report type.
4. Click on Create, as shown in the following screenshot:

5. Choose Summary Format.
6. Create a grouping for the report using the Stage field by dragging the Stage field onto the Drop a fields here to create a grouping section.
7. Click on Save, as shown in the following screenshot:

8. In the resulting Save Report dialog, enter Opportunity Stage in the Report Name textbox.
9. Enter details in the Report Description textbox.
10. Select the Unfiled Public Reports option in the Report Folder picklist.
11. Click on Save, as shown in the following screenshot:
    

We will be presented with a saved REPORT page.

12. Click on Run Report, as shown in the following screenshot:

We will be presented with the REPORT page.

13. Click on the chart icon, located at the top right of the page, as shown in the following screenshot:
    

14. In the resulting saved REPORT page, click the edit chart icon, as shown in the following screenshot:

15. Select the donut chart icon in the Display As section.
16. Enter a value in the Chart Title textbox.
17. Set the Value to Record Count.
18. Finally, click on Save, as shown in the following screenshot: