First, you need to invite the new owner to the hub as a collaborator, if you haven't already. If your hub has paid registration enabled, the new owner will need to have connected their Stripe account as well.
Now, the current owner can open the Admin Pane, click on the Settings tab and the top option will be to transfer hub ownership:
Click and follow the steps on screen to complete the transfer. Please note that only the hub owner can invite further collaborators.