Joplin uses a single page layout more akin to Evernote etc. rather than the freeform page style that OneNote allows for. There might be a combination of plugins you could use like Agenda or the TOC sidebars but currently you can't have two text areas side by side unless you implement some fancy CSS or HTML.
In which editor? You can modify a lot of the markdown editor appearance with CSS, not so much with the richtext editor.
There is a templates plugin which can help with that.