This is the standard way of opening a file. This is used when you have a file already on your hard disk that you want to optimize.
Press the Open button 
or use the File->Open menu command to start a standard Windows file open dialog box. When you find the file you want, select it and click the ‘Open’ button.
If you select more than one file you will be automatically taken to Batch wizard.
You can use the ‘Files of type’ selection to limit your choice to files of a certain type.