Generally speaking, it is not necessary to arrange it properly, as long as it is kept clean.

Generally speaking, university classrooms are not fixed. They are all arranged by schools or colleges, and usually serve as students' study rooms when there are no classes. Therefore, the classroom is not a fixed teaching place, and students usually don't stay in a classroom for a long time, so there is no need to decorate it too much.

Moreover, students in universities generally don't stay overnight after class, and few people pay attention to it except the teachers who may look at the layout of the back wall during class. But the purpose of the teacher's coming is to attend classes, and the content of the back wall is generally not concerned by the teacher.