Since NotebookLM has been rebranded as Gemini Notebook, they’ve had a steady stream of changes. The latest (as of when i’m writing this at least…) is interactive reports.
The way they have it set up, it looks like it will be a category of reports even though they currently only have one report there - Learning Overview.
To get to it, click on the reports button in the Studio section -
If it doesn’t automatically go to the interactive report tab, click on it to select
From what I’ve seen so far, the “interactive” elements are a table of contents on the left side that lets you collapse/expand it and it also lets you click on a section of the report and navigate to it (useful for longer reports)
There are also multiple places in the report where they recommend different artifacts that might be helpful -