You must do this only once when you install WpEstate theme.
How to take your buyer license code:
Login in Theme Forest with your buyer account -> Downloads:
Go to your purchase and select License Certificate and Purchase Code
Copy the buyer code from the text file
How to activate the purchase with your buyer license code:
Paste the code in Theme Options –> Notifications bar –> and click the button “CHECK LICENSE”.
This message must show to confirm the activation was successful
Make sure you activate the WpEstate Core plugin
Then you can start using Theme Options