How do Japanese students learn about their homeroom cl?

In Japan from what I've seen, they just post it on a board like you said and you just find the clroom. The clrooms are all labeled so you'll be able to find it easily. They don't bother calling out the names in an embly because it's too time consuming when you can just look on the board. Everyone takes the same cles so you don't need to ask for a schedule. Unlike in America where students move from cl to class, Japanese students stay in the same classroom all day and take the same courses as their peers. If they want to do something like art, music, dance, etc. it'll be an after school club instead of a course. They put more emphasis on examination scores rather than what courses you take.