Second Level page URLs

I have a few client sites I am setting up under my profile. I need to create second level URLs for the pages, like /about /events… while having them connected to the clients URL.

Right now, they just show up as my readymag profile link.
For example the homepage is https://clubsocialbutterfly.com/

From this I need to create clubsocialbutterfly.com/about
for the about page. But readymag has it set to a link from my readymag account https://readymag.com/nicholasjacksondesign/4558912/

How can I change this to connect to a second level URL structure?

You can set two-level structure straight from the ‘Pages menu’. Just drag the page and hold it for a while. Check the screenshot.
BUT it’s not possible to combine different navigations (Horizontal and Vertical) in one project.

As you are using the ‘Home project’ already in your reference you should Unmap subdomain from this project and set the custom url to ‘about’ (menu Pages again)