Where do you have to enter the code for Zonewars fortnite?

Where do you have to enter the code for Zonewars fortnite?

At their website at Epic games

Can you please give me a more detailed information, such as where I need it or something, whether I should do it from the ps4 or from the phone or PC?

On ps4, pc and mobile phone is not. You go to Epicgames.com then you sign up with the acc on which you want it, then you go to the three bars on the top right then look where there's redeem code