Embedding a Sketch on a page
Type /sketch anywhere in the Confluence page editor. If the space has no Sketches yet, or you choose to start fresh, you're straight into a blank canvas — there's no separate configuration step first. Close the editor and the Sketch is on the page.
A picture, except the cards
Rendering a Sketch as a static image on the page means a page with several diagrams on it still loads fast, rather than becoming several editors someone has to wait for. The one exception is any Confluence page card on the canvas: those stay live, and read their current state without anyone reopening the diagram.
Editing it again
There's no click-to-edit button on the drawing itself. Select the macro and use Confluence's own toolbar — the same edit, align, copy and delete controls any macro gets — and choose Edit to reopen it in the full editor.
Embedding stores a reference to the Sketch, never a copy of it. The same diagram on three pages is one diagram — edit it from any of them and all three are right, instead of three copies that drift apart at their own speeds.
A macro pointed at a Sketch that's been deleted, or one pasted in from elsewhere, shows “No Sketch chosen — select this macro and choose edit to pick or draw one.” An empty Sketch — one nothing has been drawn in yet — says so too, rather than rendering a blank rectangle.