Publisher Studio is where you turn a world into a document you can actually hand to someone: a client proposal, a report, a public page. It's a distinct authoring surface, not just an export button bolted onto the graph.
It's a Pro feature. Everything else on the free plan works exactly as normal, see Account & Billing for the full picture.
The page editor has its own formatting toolbar, separate from the regular node-notes editor in Right Panel (Notepad): block type (paragraph, Heading 1/2/3), bold, italic, underline, strikethrough, text alignment, plus document-level font family and font size. It also supports multi-column layouts, and a slash menu kept deliberately narrow (headings, quote, lists, paragraph, divider) since this is for finished documents, not freeform notes.
Two square brackets works here too, and does the same thing it does in notes: you get a hyperlink from one page to another, useful for a contents page or a cross-reference in a long document. It's a link, not a connector, so writing and rewriting a document never rearranges the graph behind it.
Each page can have a cover image. Click "+ Add cover image" above the page title. Once set, you get Reposition (drag to adjust the crop vertically), Change, and Remove controls. It's stored directly on the node, so it travels with the page if you move or rename things.
When you're ready to get the finished document out into the world, see Publisher Studio: Sharing.
Still stuck? Email [email protected].