We’re creating a new official tutorial for Wagtail as part of Google Season of Docs, bridging the gap between the existing "getting started" tutorial and our fully-fledged bakerydemo demo site. Want to see the bakerydemo live? There’s a static copy there: static Wagtail 5.2.
We still have lots of writing to do, but the site’s code is all done at thibaudcolas/your-wagtail-portfolio if you want to take a look.