Can't change themes and add plugins

thanks for such a great product! It’s fast and easy to install!
However, I can’t start using it to create my webpage, because I don’t have access to internet from the Theme and Plugin pages in Wordpress and can’t download themes and plugins. When I add my theme directly to the theme folder (on ~Local Sites), I still cannot see it in Wordpress. What I see is only Twenty Seventeen theme, and unable to change it. Same with plugins…
I tried to restart the machine, I also uninstalled the local and installed it again - nothing helps(((
Is there a solution to my problem?