In order to activate an Epic Games code:
Visit epicgames.com and sign into your Epic Games account or create a new account if this is the first game you activate in this platform.
Once you're logged in, use this link to activate your game.
Enter your key and click "REDEEM".
Alternatively, you can also activate your key through the Epic games application.
Launch your Epic Games application.
Click on your account name on the top right and then click Redeem Code.
In the page that shows up, enter your key and click "REDEEM".