doc: Explain in README where to find artifacts

README.md

@@ -4,5 +4,22 @@ This is an attempt at an introductory lecture notes on programmable cryptography
 It is developed by [0xPARC](https://0xparc.org/).
 The source files are written in [Typst](https://typst.app).
 
+## Downloading the book
+
+- If you want the latest **tagged** version (i.e. that has a release number),
+  check the [Releases page](https://github.com/tideofwords/0xparc-intro-book/releases/).
+  We tag the versions of the book as they reach certain milestones,
+  e.g. just before we send them off to the printer.
+
+- If you want to download the compiled book as of the latest commit,
+  go under the [Actions page](https://github.com/tideofwords/0xparc-intro-book/actions)
+  and click the most recent commit.
+  Scroll down until you see the section titled "Artifacts" and
+  click the link labeled "PDF".
+
+![Where to find artifacts for the latest compiled build.](artifacts.png)
+
+## Spot a typo?
+
 You can download PDF's from the releases on the right
 (they are also uploaded as artifacts on every pushed commit).