The license key is sent to you in an e-mail message. Once you have received the license file, copy it to your computer and restart SAP Business One. When the license query appears, add the license file to it. You can also download the license key from the SAP Channel Partner Portal at http://channel.sap.com/sbo/licensekeys.
If you need SAP support for help with license keys call (866) 256-4150 or send an email.