Another random idea: fork an open-source intro book (like this one) and revise it for someone starting on Anvil from the very beginning. It could start by having them set up a free Anvil account rather than install Python. Then “Hello, world” can be output to the Anvil Output pane using a module as the startup: https://anvil.works/build#clone:5N6NFPYDH3I37E4F=EX7Q67NBUUX23JPVLI6DM6KL
But as appropriate concepts are introduced, the examples can be adapted more and more to Anvil. For example, the Anvil button could be used to explain the concept of an object.
(edit: Added demo with a startup module, as suggested by @p.colbert.)