The first thing to do is to go to the options menu. Choose the PDF profile, then enter the Advanced settings. From that menu, look for the application that says Create one PDF file for each scan. Now, go back to the scanning operation and initiate the scanning to PDF. You can scan multiple pages and at the final, one PDF file will be saved.
If the application still has issues with multiple scanning procedure, use an application from the database of Software Informer to join those files.