Hello,
It’s pretty easy to activate the license key. Follow these steps:
Download the theme and activate the pro file on your website dashboard > themes > Add new > upload.
After that, go to My account of our website and find the license key. Copy that license key and paste in the dashboard > Appearance > themes license> set the key there.
Is it possible that the browser you’re using isn’t showing it? I was using Brave not long ago and kept getting weird issues like this (although not this exact issue). Switched it up to Firefox and now it’s fine.