Visit this page to download the Readiris PDF 23 software. 

http://www.irislink.com/support/iriscanbook7

Once installed and activated 

1. Plug the scanner into the computer and it will automatically go into USB mode. 
2. Click the From File button to import the images stored as JPG or PDF files that are stored on the scanner.
3. Make sure the Append switch is set to the left.
4. Click the PDF button in the quick convert section on the Home tab to output to a single output file.