Here is the easiest way for you to activate the License Key for the plugins

Divi Next Website → Your Account 


Sign in to your account on our website: https://www.divinext.com/your-account/ and then, copy the License Key from your account.

WordPress Dashboard → Plugins


Head to your WordPress Dashboard and go to Plugins, here you paste the License Key onto the License Key field

  

Save Changes → Activate License


After applying the License Key to the License Key field, you have to first click ‘Save Changes’. And then click on ‘Activate License’.


Here's a video that shows you the process as well:

https://www.youtube.com/watch?v=0GWWaFM0jzM

I hope this was helpful


Thank you