Have you tried the “Download code” option in the notebook menu in the upper right?
This screenshot is from the beta version of Observable, in this case https://next.observablehq.com/@d3/sortable-bar-chart (the “next.” at the start gets you the beta), but it’s also in ‘classic’ Observable.
That’s the compiled source of a notebook. I know it can look sort of intimidating, especially if you’re also new to D3; it’s not easy to copy and paste the whole thing directly into a different environment. We think the price is worth it, because it’s necessary to make Observable a nice reactive place to code, but it can definitely be frustrating! I once went through and annotated an example of what you get from that download, which might be helpful: An Observable Notebook.
We also have embedding options for if you want to just e.g. paste in an iframe somewhere: https://next.observablehq.com/@observablehq/introduction-to-embedding?collection=@observablehq/embedding-notebooks