someone talk me through performing an seo audit?

Rough order I'd go in: 1. Search Console first - the Pages report tells you what isn't indexed and why. That's usually the biggest finding. 2. Crawl the site (Screaming Frog's free version does up to 500 URLs). Look for broken links, redirect chains, missing or duplicate titles, and pages with no internal links pointing to them. 3. Check speed and Core Web Vitals on your main templates, not every page. 4. Content - thin pages, pages competing for the same keyword, stuff that's out of date. Then rank what you found by impact. An audit that hands you 200 issues in a flat list doesn't get acted on.