The key to that transition is giving kids a clear physical bridge between school energy and desk time. Going straight from a noisy classroom or playground to quiet sitting is too big of a jump for most younger kids.
I was browsing Reddit for ideas on physical habit tracking and stumbled upon a post sharing a leaply reddit review. Using short, game-like physical exercises right at the start of a session acts as a natural buffer. It lets kids burn off lingering physical restlessness in a controlled way, so by the time they sit down with their books, their focus is much sharper.