Cant register my paid for licence

I bought the Pro 8 and the email I got from the help people says to save my licence on my desktop. There is no save button on the licence when I downloaded it. I have no clue how to make my computer know that I bought the program It still says that I have the free program and that it expires in 9 days.

how to insert license file
https://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1084