Cannot Install New WordPress Theme Using Filezilla

Hi there, my site is https://www.nobigwhoop.net
I’ve been trying to install a new theme that I downloaded from this website- https://topwpthemes.com/
but have been unsuccessful. I followed the instructions on the site, and it told me to download Filezilla. I trust that most of you have used Filezilla, so you’ll understand when I say that it asks you for a HOST, USERNAME, and PASSWORD.
For host i put https://www.wordpress.com, and enter my wordpress username and password accordingly. It then tells me that it “could not connect to server”

Am I putting in the proper information?
Is there an article that guides you step by step on how to install a wp theme using filezilla, because it is tremendously confusing for me.

Thanks in advance.