There will be a set of rules for parents and a set for pupils. Parents’ rules may look like a particularly repressive contract of employment, with strict instructions to inform the school of the least departure from your child’s normal routine.
The pupils’ rules will indicate how much restriction the school places on its pupils and the importance of traditions such as ‘only sixth formers may walk on the grass’. Many schools do not publicise their policies on serious issues (smoking, drinking, sex or drugs) because they believe parents will assume that the mere mention implies they have a problem. Other schools have a good, clear code of behaviour and tariffs of penalties, sometimes agreed with the pupils themselves.
Some children flourish in a fairly regimented environment, others find it a strain to be constantly bumping up against authority. Your child is likely to find life less confusing if the approach to rules is broadly similar at school as it is at home.