Google Analytics 4 replaced Universal Analytics in July 2023, so every site now runs on GA4's event-based model. You start by creating a GA4 property in your Google Analytics account, then install the measurement ID tag (G-XXXXXXXXXX) either directly in your site's header or through Google Tag Manager. The GTM route gives you more flexibility for custom events without touching code every time. GA4 automatically tracks page views, scrolls, outbound clicks, site searches, video engagement, and file downloads as events. You don't need separate tracking codes for these like you did in Universal Analytics. Custom events—form submissions, button clicks, product views—get set up in the Events interface or through GTM triggers. For ecommerce, you'll implement the ecommerce events schema, which requires more structured data than UA but gives better purchase funnel visibility. The Reports tab shows pre-built overviews (acquisition, engagement, monetization, retention). The Explore tab is where you build custom reports using dimensions and metrics—this is more powerful than UA's custom reports but has a learning curve. Set up conversions by marking key events (purchases, lead forms, phone clicks) as conversion events in the admin panel. GA4's big advantages are cross-device tracking through Google signals, better integration with Google Ads, and predictive metrics like purchase probability. The tradeoffs: historical data doesn't migrate from UA, the interface is less intuitive for people trained on UA, and some reporting dimensions (like exact keyword data) are more limited. At Ottawa SEO, we run GA4 alongside server-side tracking for clients with complex funnels because GA4 still loses 15-30% of events to ad blockers and iOS privacy features. For most businesses, the standard GA4 setup covers what you need—just make sure you're tracking your actual business events, not just the auto-captured pageviews. Configure your data retention to 14 months in settings, and link your Search Console property for organic search data.