After purchasing Music Production Suite 6, you will receive an email containing all your serial numbers, including your Melodyne 5 Essential serial number.
Please note that Melodyne is not installed via Product Portal or Native Access.
Registering and downloading Melodyne 5 Essential
Visit this page to create a Celemony account (if you haven't already).
Once logged in to your account, visit this page and click Register serial number.
Enter the serial number you have received via email and register it.
Now you can download Melodyne 5 Essential directly from the License Overview page.