Class - constraints
For each class you can set core constraints. In dialog "Classes", select the class and click on the button "Constrains". The dialog "Class details" will appear:
In this dialog you can:
A: You can allow the class to arrive on second period.
See also: Children can come to the school on second period, but only once per week
B: Set more advanced options in the education block.
See: Education block - allow some classes to come later or to leave school earlier.
C: Set the maximum allowed number of lessons on question marked positions, in class's Time-off.
See: How to specify that class can have max one 7th lesson or max one 0lesson?
D: Enter the maximum allowed number of lessons per day that require preparation.
See: שעורי הכנה
E: Decide if the groups of students have to finish the day at the same time.
See: שתי קבוצות הלימוד חייבות לסיים את יום הלימודים באותה השעה
F: Allow one free period for Lunch.
See: How to specify when a class can have a lunch?
G: You can set that the Class teacher must teach the class in a specific time during the week.
See: Our class teachers always have to teach the 1st lesson
Note:
You can input these options anytime later during the timetable creation process. So for a start you can ignore them and maybe later, when you will be improving your timetable, you can input more of these constraints.