You can display Information on your own lessons using menu item <Lessons> | <My lessons>. You can specify here which students actually take part in a particular lesson in the event of split lessons.
The buttons under <Appointments> provide an overview of each individual lesson period.
Go to <My lessons> in order to send a message to the students attendign your lessons.
You can display the lessons for a teacher or for a class for the selected day in the calendar via <Today's lessons: Teachers> and <Today's lessons: Classes>. Provided you have the appropriate rights, you can e.g. open the class register , create new exams, shift lessons or cancel them, create additional periods, make room changes, etc. via the list of displayed lessons.