proceeded to the Avast web site and used the registration there

I was sent the registration code, but cannot enter it
It says (in the email) to open AVAST, choose Maintenance, and then ‘Insert the license Key’ at the bottom of the screen

there is no such
All I have is a button

which if I use again attempts to sign in, but then ends with ‘Web Service unavailable’
so now I have a registration code, but no place to put it

Oh yes, and when I clicked on
https://support.avast.com/index.php?languageid=1&group=eng&_m=knowledgebase&_a=viewarticle&kbarticleid=1037

I get a untrusted certificate warning from google … its your site and its not right?

even when I get to that site, AND enter my password and so, I get nothing, the video doesn’t play nor is there any option