Multisite WordPress

I am currently in the 30 day trial (Smush Pro) and it looks like I get access to all the plugins. There are a couple of plugins that are greyed out because it requires "Multisite." I have created 2 parallel websites (clones with one in dark theme ( and the other using a light theme ( Currently all posts that were present and scheduled in future are on both sites. However when writing a new post (say on I am having to copy and paste it and schedule it on the light mode. I was wondering if your Multisite Content Copier would be perfect in this application, and what steps do I need to get multisite?