# Starter Components > **Load when:** Needing device frames, slide deck shells, presentation grids, or animation scaffolds > **Skip when:** Designing from scratch with existing components, or building something none of the templates cover > **Why it matters:** Avoids hand-rolling scaling logic, device bezels, and animation engines — these are tricky to get right > **Typical failure it prevents:** Hand-written scale transforms that break on resize, slide decks without proper letterboxing, animation timing drift Starter components are ready-made scaffolds in the `assets/templates/` directory. Copy them to your project instead of hand-drawing device bezels, deck shells, or presentation grids. Kinds include the file extension — some are plain JS (load with ` ``` The page MUST call `window.postMessage({slideIndexChanged: N})` on init and on every slide change. `deck_stage.js` handles this automatically.