Please see the Gemara Brochos Daf Hey, Amed Aleph, concerning your question as it states openly that everything was given on Har Sinai.
There is some question as to what form it was given it whether it was the actual words or the Clalim (rules and principals) as seems to be the case from the Medrash in Shmos Rabbah.
The reason why these things are not taught in more specificity in school is probably because of the complexity as there many Gemora’s and Medroshim on the subject and it is something that does not allow for mistakes as a mistake can lead to Kefira please see the yud gimeel ikrim.