Welcome @mad_brain !
Here are some quickstart ways to start out with Matomo:
- play around with a live dashboard, with all of the optional plugins running: Matomo demo
- a list of every feature is here: features list
- a seven minute video is here: What is Matomo Analytics?
Access more than 3 hours of video training covering all of Matomo Analytics features, as well as the Tag Manager:
- Matomo Analytics Training → 21 videos
- Matomo Tag Manager Training → 12 videos
- https://matomo.org/guide/videos/videos/
- https://video.matomocamp.org/videos/trending
And some books are available: