The two modes
Source shows the raw HTML. Everything is editable, nothing is interpreted for you — this is the mode for pasting an export, tuning a table layout, or fixing an inline style. Visual shows one field per editable zone declared in the document. It exists only when the document declares zones, and it can only rewrite what is inside them: the header, the footer and the unsubscribe link stay out of reach. A live preview sits next to the editor, in desktop and mobile widths, rendered exactly as a real send would render it — merge tags filled with sample data.Starting from a design
The catalogue offers ready-made documents, alongside the templates you already own. Picking one replaces the whole document with the design's, which is why you are asked to confirm when something is already written. A design is a starting point like any other: once picked, it is yours, and nothing links it back to the catalogue.Testing before you rely on it
A test send delivers the template to an address you choose, with sample data filled in and an unsubscribe link that unsubscribes nobody.A test is a real send. It goes out through the same path as a campaign and counts against your
sending quota. It counts in no statistic, though: no open, no click, no progress.