Are the kids on laptop/screens all day?
Definitely not! The kids break twice in the day for recess and lunch, to go outside and run around (weather permitting). The classes generally go for 1.5-2 hour blocks so kids can spend some quality time working on their code!
Our Head Teachers do break up these periods with times when the kids will close the computers to focus on the front of the class, as well as some interactions and brainstorming between the whole class.