I’d like to install BuddyBoss (a WordPress plugin) into Webflow. I checked with BB and they said it should be possible as long as my web host met their requirements, which it does. But how to add a zip file to Webflow?
You can’t. I believe they gave you misguided info. Wordpress plugins will not run on Webflow. You could design a site and then convert it to Wordpress using some available tools.