Hit the run button to start searching email-addresses. They will be shown in the left pane while they are found and while they are being written to the output file. In the right pane the addresses are shown, which are excluded from the output file caused by eventual filter settings. If you happen to see an address which you want to add anyway, then click the "Add anyway" button and it will be added to the end of the output file.
Hitting the sort button will sort the found addresses on screen + in the output file.
Note: before hitting the run button it is better to close Outlook itself, in order to make sure that Pst2mail can look freely in the pst-files.
Tip: Double-click under the run button on the label "Found (added to output-file)" to open quickly the output file.