Where they should go and what should they do?
No further than their own computer, don't take verbatim 'facts' from "experts", because they are usually wrong, anyone offering a cast iron, copper bottomed, 100% fool-proof, guaranteed way to "SEO your site" IS lying.
Read everything you can find, but don't believe any of it, You can take what actual search engine employees say as being reasonably accurate, particularly what not to do, but these are NOT 'rules' they are just guidelines. You have to determine what is actually 'best' for your pages as no two sites are ever alike, and what 'works' for one marketplace could be a disaster in another.
The best idea is to simply ignore search engines and put all your effort into just getting real traffic and real customers, forget about irrelevant metrics, such as "bounce rate", "time on page", "unique visitors", etc. if your site is commercial in any way which includes being 'ad supported', the only thing that matters is conversions anything else is just 'window-dressing'. The thing that every body considers 'weird' is that when you do 'optimise' for real people you find that you also get traffic from Search. This is because when you market to real people you also give search engines exactly what they want as well.
Good content, aimed at real people, because search engine users ARE real people as well.