Double Sided Printing? Facing Pages? Spreads?

If the book will be sent to a printer and the binding is folded at the spine, which is the case for most book binding methods, set up the document as Facing Pages. With facing page documents the pages panel includes a spine mark indicator.

You have to deliver single pages to a commercial printer, not spreads, because the printer will be imposing (rearranging) the pages for their press sheet.

Whether to choose single pages or facing pages is up to you.

If you want running heads and page numbers on opposite sides of the pages (like a magazine or book) then you should pick Facing Pages and insert that info on the Parent Pages. 

Facing pages is also good if you need different margins - often in print you need a header margin, a footer margin - an inside and outside margin.

If it's printed profesionally, in what's called Saddle Stitch or Perfect Binding - then you would need a bit of extra space on the Inside margins to account for fold/glue/threadsewn etc.

It really depends on what you're doing.

If you're printing it yourself to paper on both sides, you don't need Facing Pages. Single page will do.

If you want a booklet - then Facing Pages.

When done - export the document to a PDF

Then in Acrobat choose your print options from there.

If being printed professionally - single pages with crop/bleeds etc. 

Ask your printers for directions here. 

You don't typically need to export as spreads.

And you should also follow logical page order from page 1 to page 8 or page 12 or how many pages there are. 

See here I found online
https://www.askdesign.biz/blog/2022/05/indesign-single-pages-vs-facing-pages/