1. Click on the file, in the default information column, click on the cleaning tool, and then click on the archive
2. Select the folder range and time, and click Browse
3. Select a local path, then enter an easy-to-understand name in the file name, and click OK
4. Finally, click OK in the archive dialog box. The synchronization progress will appear in the status bar below the email, and it will take a few minutes for the synchronization to complete
5. The synchronized pst files can be merged according to this tutorial: Merge Outlook mail archive pst files