Free primers and full curricula — read one, then practice it.
Every Keentune skill can be practiced straight away, and many also come with something to read first. A guide is a short primer — about fifteen minutes — covering the mental model, the mistakes people make early, and what to drill first. A curriculum is the complete concept list behind that skill’s adaptive practice, chapter by chapter, so you can see exactly what mastering it involves before you start.
Both are free to read, with no account and no card. Signing in only adds the bookmarks: which chapters you have finished and where you left off.