There are two main ways to select the data source for a PivotTable in Excel:

1. Using an Existing Table or Range:

* Click anywhere within your existing PivotTable to activate it.
* Go to the Analyze tab on the Excel ribbon.
* In the Data group, click Change Data Source.
* A dialog box titled "Change PivotTable Data Source" will appear.
* Select Use an existing table or range.
* In the Table/Range textbox, enter the cell range of your data (e.g., A1:D10) or select the table directly.
* Click OK.

2. Using an External Data Source:

* Click anywhere within your existing PivotTable to activate it.
* Go to the Analyze tab on the Excel ribbon.
* In the Data group, click Change Data Source.
* A dialog box titled "Change PivotTable Data Source" will appear.
* Select Use an external data source.
* Click Choose Connection.
* This will open a separate window depending on your data source type (e.g., Access database, text file). Choose the appropriate connection method and follow the specific instructions for connecting to your external data.
* Once the connection is established, click OK in both the "Choose Connection" and "Change PivotTable Data Source" dialog boxes.

By following these steps, you can easily select the desired data source for your PivotTable, allowing you to analyze and summarize your information effectively.