The original source data has a column of Order Date information, so there is an Order Date field on the PivotTable Field List. That means you can get the answer to another question: What are the sales by date for each salesperson? To get the answer, select the check box next to the Order Date field to add the field to the report.
The Order Date field is automatically added on the left, in row label orientation. That's because the field does not contain numbers (dates may look like numbers, but they are formatted as dates, not numbers). Because the Order Date field is the second non-numerical field to be added to the report, it is nested within the Salesperson field, indented to the right.
Now the report shows sales for each salesperson by individual date, but that's a lot of data to view at one time. You can easily get this data into a more manageable view by grouping the daily data into months, quarters, or years.
To group the dates, click a date in the report. Then on the Options tab, in the Group group, click Group Field. In the Grouping dialog box, select Quarters, which seems like a good solution here, and then click OK.
Now you see the sales data grouped into four quarters for each salesperson.
Click Play to see how to add the Order Date field and then group a field.