If your site doesn't match the live preview, work through this checklist:
1. Required plugins: make sure every plugin from the theme's setup notice is installed and active. Missing plugins (sliders, page builders, WooCommerce) are the most common cause. 2. Permalinks: go to Settings → Permalinks and click Save once. This flushes rewrite rules and fixes many "page not found" and layout issues. 3. Menus & widgets: if you didn't run the demo importer, you'll need to build menus (Appearance → Menus) and set widget areas yourself. 4. Caching: clear your caching plugin and CDN, then hard-refresh the browser. 5. Homepage: set your homepage under Settings → Reading → "A static page", and pick the page the demo uses as the front page.
Still off? Open a ticket with a link to your page and a screenshot of the difference.