How do I see a folder structure of pages within confluence?

[Stephen Deutsch]

You could click on the "Space Tools" in the bottom-left corner of the screen, then click "Reorder Pages", and then you will be able to see a tree view (like a folder structure) of all pages in the space.  You could also use the pagetree macro as Nic recommended.

[Nic Brough -Adaptavist-]

I'm not quite sure what you're looking for here, so I expect this answer to be inadequate in itself, but hopefully you can point at it and explain what it does not do that you need.

Have you tried the pagetree macro?  You get the structure of nested pages laid out for you in there.  It doesn't go above a space level, but you can imagine a simple flat "every space is one branch under Confluence" for that part.