Select the pages and disable shuffling, then drag them together.
In case it's not obvious,, you can disable page shuffling from the Pages panel menu.
You can also create a non-Facing page document of one page, disable page shuffling, and use the Insert Pages command.
Thank you Peter Spier and Steve Werner. It is not at all clear what "allows shuffe pages" means, so I had that enabled because I was trying to move pages.@