To activate a Promo code you have to Sign in first.
You’ll get on your account Events page upon authorization. Click the “Upgrade” button in the upper right of the screen.
That click will take you to the Subscription Purchase page.
After selecting a plan and additions (if you want to purchase additional functionality), click "I have a promo code" near the "Pay" button.
In the menu that opens, enter the promo code and click "Redeem".
The amount will be re-calculated and then click "Pay" to pay at a discount.
A short video tutorial:
If you have any questions left, feel free to contact Proficonf customer support or write to email@example.com.