Cards are laid out in collector-number order, so every card sits where it belongs in the set. Cards already in the binder from this slot onward move along to make room, and cards of this set that were already placed elsewhere in the binder are moved here.
The type decides which cards “Add set to page…” lays out; you can still place any card by hand. Full-art follows Scryfall's full-art flag.
Count each side of a sheet as one page. You can change the layout later; cards that no longer fit go back to your unplaced cards.