If you know how to use wildcards and want to use them, this is the place to do it.  The dropdown box will help you with a selection of file types.  Select a file type or enter your own.  Press the Include button to include those files in the backup or press the exclude button to exclude them.

 

Click on the OK button to return to the Files to Backup main screen.  If you chose to include a file type in the previous tab, those files will be checked in the Files box.

 

The other way to select files is to click on the file in the Files box.  Check the files that you want included in the backup and uncheck the files that you do not want to include.