Each template is authored once in MJML and compiled per-ESP with that platform's merge-tag syntax. Pick a variant to view a live render.
Full template = paste into EO's Code your own editor. Snippets = paste into EO's drag-and-drop editor (one per Code content block) so editors can add/remove/reorder sections via the UI.
Paste into CM → Templates → Custom-coded template. Repeater + layout system lets editors compose from the layout palette.