Slightly off-topic, but how are children dealing with non-fixed classes? Thinking about 7 year old children (or even adults), getting on time from one to anothe

Slightly off-topic, but how are children dealing with non-fixed classes? Thinking about 7 year old children (or even adults), getting on time from one to another classroom according to an indvidual schedule would not be an easy task. Are there provided with extra help, like single-purpose classrooms according to subject? Do teachers announce where the next lessons take place? Are students split into sub-groups sharing the entire schedule, so they can team up and not lose track of it?