How to activate additional users?

How to activate additional users?

I would like to check, how do I activate additional users that I've already purchase? Let say I have 3 free user. And I purchase additional 5 users license, where to key in the activation code in the setup? Currently using on-premise edition. Really hope Zoho CRM will release an updated version instead of the current version 5 with some minor bugs. Zoho CRM is a very good CRM. I really love it. Thanks!