On the child's page there is a “Steps” tile with today's count. Tap it: “Today” and “Yesterday” by the hour, “7 days” and “30 days” by the day, with the total and the daily average. The child sees their own “Steps today” on their screen.
The child's phone counts the steps itself with its own sensor while the phone is with the child — in a pocket or a backpack; at school and at home too. A phone lying on a desk counts none. The number is approximate, like a fitness band's. It needs the “Physical activity” permission on the child's phone; many tablets have no step sensor.
Today's steps are always shown; past days need the subscription, like the history of places. Steps are kept for 31 days.