pdf folder displayed on page with drill down

You could take a few different approaches to create a page with folders to drill down to and searchable PDF files by periodical and date on an archived newspaper site. Here are a few ideas:

1. Use a WordPress plugin like WP File Download to create a file manager interface on your site where users can browse and search for PDFs by folder. This plugin allows you to create custom categories and subcategories, and you can set up the folder structure to match your existing file organization.
2. Use a WordPress plugin like Gravity Forms to create a custom form that users can use to search for PDFs by date. You could set up fields for the periodical name, year, and month and use a hook to search for PDFs in the corresponding folders when the form is submitted.
3. Use a custom WordPress query to display a list of PDFs in a specific folder on a page. You could set up a template for the archive page and use the query to retrieve PDFs from the appropriate folder based on the periodical, year, and month selected by the user.
4. Use a combination of the above approaches, such as a custom form for searching by date and a custom query to display the results in a list of PDFs.

I hope these ideas give you some direction for creating an archived newspaper site with searchable PDFs organized by periodical and date. Let me know if you have any questions or need further assistance.