If you have not received a license file, then you need to copy the ID string that is shown in the dialog by clicking the "Copy" button and then send the ID string to your I-CONIC sales representative, who will generate a valid license for you.
If yo have received a license file from I-CONIC, then you browse to the location for the license file to enable registration of the license. Once registration is done, you will not need to have the license file available anymore, but it is recommended that you keep it for reference.