You can install a Hub item with a data subscriptions just like any other Hub item from the Maltego Desktop client’s Transform Hub and no API key is needed. Please note though that such Hub items are only available in the Transform Hub after a successful purchase of the data subscriptions and completion of the KYC vetting process. Only then you should be able to see and install the Hub item from the Transform Hub. In case this doesn’t work, please refresh the Transform Hub or restart the Maltego Desktop client.