Via 'Lessons' in your data entry wizard you can define your lessons.
Enter the number of required weekly periods, the subject, class, teacher and the room.
The example above shows a mathematics lesson with 4 periods in class 1a with teacher Gauss in room R1. By clicking on <Save & New> you will create this lesson and will start creating a new one.
If several classes or teachers are involved in this lesson, you simply add them.
Students of classes 1a and 1b take part in the double-period RK lesson. This way, you can also define an additional special tuition teacher, a trainee, team teaching, etc..
If two or more teachers shall teach two different groups of students at the same time you simply create every lesson separately (e.g. sports lesson for girls of class 1a with teacher Curie and sports lesson for boys of class 1a with teacher Gauss). Only to a later point in time of the scheduling process you define that both lessons take place at the same time. You therefore define two separate lessons, one with Curie and one with Gauss.