You have to add the initial markdown to the DOM outside the event handler on first load. If it only happens inside the event handler, it won’t run unless the handler does.
However, the requirements states what must be included in the initial markdown, which is more than just a h1. When you run the test, it will tell you what elements should be included in the initial markdown. You can also look at the example project.
The initial markdown should be added and rendered on first load.