Good afternoon,
You must log into Hauptwerk.com account then purchase the license migration package - https://www.hauptwerk.com/hauptwerk-v-license-migration/. Once your order completed, keep your browser open then go to https://www.hauptwerk.com/prevvilicensemigrations/, press the 'Hauptwerk License migration' button.
You should be able to complete the form now and upload your file to migrate your licenses to iLOK.