Add lessons that nest under a course

With a course landing page in place, you add its lessons as separate posts. The mechanism that makes a lesson "belong" to a course is the primary tag: a lesson whose primary (first) tag is the course's public tag automatically nests at /courses/{course-tag}/{lesson-slug}/ and appears in the course's curriculum sidebar.

Create a new post for each lesson. Give it a descriptive title and a slug that includes the course and an ordering hint — the convention used across this site is {course-tag}-NN-{lesson-title}, for example apex-masterclass-01-apex-language-fundamentals. The numeric prefix is a human convenience; actual ordering is by published date (see the next doc).

Lesson post tags (in order):
  1. apex-masterclass        <- PRIMARY: the course's PUBLIC tag (this nests it)
  2. #lesson                 <- marks the post as a lesson
  3. #level-*                <- optional, inherits/annotates difficulty
  4. #free / #paid           <- access; #preview to sample a locked lesson
  5. #lesson-type-video + #video-duration-*   <- only for video lessons

The critical part is tag order. The first tag must be the course's public tag, because Ghost treats the first tag as primary and the theme keys nesting, breadcrumbs, and the sidebar off it. After that, add the internal #lesson tag so the post is recognised as a lesson. Then layer any presentation tags: a #level-*, and for a video lesson add #lesson-type-video together with a #video-duration-* tag so the card shows the runtime.

Write the lesson body with clean heading structure (an h2 to open, h3 for subsections) so the auto-generated table of contents is useful. Include code blocks with a language class where relevant — the theme styles <pre><code> for readability.

Publish, and the lesson immediately appears under its course. Repeat for each lesson. The one thing left to control is their order, which is driven entirely by the published date — the subject of the next doc.