license plugins

Hi, I bought two licenses for the Highend Theme.
One is already in use on my site but when I go to the revolution slider I get the notice that I need to activate, the license key I got doesn’t seem to work.
The other one I just uploaded to a new site, and I can’t find where I can enter the license for the theme and same thing for all the recommended plugins (revolution slider, visual builder etc).
Thanks,
Camilla