A lesson is the unit a member opens: a title, Markdown text, one video reference and a list of resources. It belongs to a program, optionally to a course, and optionally to a section inside that course.
A lesson is born a draft and stays invisible to members until you publish
it. Archiving one is not terminal, unlike a program or a course: the
platform allows archived → published, because pulling content back is a
decision you may want to undo.
Resources come in two shapes and never both at once: a link carries a url,
a file carries the mediaId you get from the upload endpoint — every
uploaded file is listed in the school's media library.
Information
Writing a lesson requires OWNER or ADMIN in the school — writing content is
the same gesture as composing the structure that holds it.