Enfold Installation Error

Hi team
Im trying to set up enfold theme for the first time on a brand new WordPress installation. I went into my envato account and downloaded the enfold theme, but when I try to upload it through my WordPress dashboard, I am getting this message:
“The link you followed has expired.”

So using cPanel as a different method, I have uploaded just the enfold.zip (files only) and unzipped it. I did the same for the enfold-child theme too. They both appear in WordPress dashboard within the Themes window as they should do. However if I try Live Preview the theme before activating it, it warns of:

“There has been a critical error on your website. Please check your site admin email inbox for instructions.
Learn more about debugging in WordPress.”

If I ignore the live preview and just activate the theme, the site fails and is just a plain white screen.
WordPress and the website works fine with the other default themes activated, it is only with the Enfold and Enfield child theme that has this problem.

HAs anyone else experienced this, can you support me and let me know what the problem is and/or where I can find instructions as to the solution.

I appreciate any help or assistance you can give me.
Keep safe and well
Matt