If you already have installed the StarForce Reader, adding additional eBookss is very simple.
You DO NOT have to download and install the Reader again.
After installing the Reader, you must

1. On the top Toolbar click on ‘Add Book’ option. When prompted, enter the serial number that you received via email
2. Once the download and the extraction process is complete you will be able to access the additional product via the ‘Installed Books’ option in the toolbar.

Please see the StarForce website.