Please visit https://www.groove3.com/redeem
Registration to the Groove 3 website is FREE.
If you already have a User Profile with Groove 3, please login to download:

Revoice Pro 4 Explained® from Groove 3 is a free download and it is yours to keep.
To access your download link, click the Complete Order button...

... and your download link will be shown in your Order confirmation:
If you have any question, or if you encounter any difficulty, please email support@synchroarts.com for assistance.