Hi, just divide your document into page sections "page panel/numbering and sections item" - choose new section in the place, where you plan to insert blank pages and set numbering not automatical, but the contunuing number of layout. Then insert your blank pages at the end of fisrt section and make it separate section with different kind of numbering (for instance greek), so your page numbers will look for instance like this 1-34, I-II (blank pages), 35-286.
Adding a blank page in ID is just like trying to put a blank page into a physical book. In the physical world, pages have two sides, so you cannot create a blank surface on one side only unless all the folowing pages shift from front to back or vice versa. Same thing in ID. Add one page anywhere but at the end, and all the following pages will switch sides, add two pages and you get a front and back that can remain blank or be filled with content, but your other pages remain undisturbed except for automatic numbering.
If you want to skip numbering on a page or pages, you must remove any numbering markers from those pages (all pages have number assignments) and add two new section markers, the first on the page where you want numbering to stop, and the second where you want it to restart. The reason for setting two sections is that if you don't change the "numbering style" or assign numbers that fall beyond the page count of your book for any blank pages, you will wind up with overlapping duplicate "logical" page numbers (they're assigned, even if they don't appear) and ID will warn you that there are multiple pages with the same number and will not be able to do page range operations like printing using the logical numbers.