I have Geography two times per week. It shall not be on consecutive days.
Select Geography in the subject list and press button "Constraints".
Then change the Default carddistribution over the week to "Ideal/No Consecutiive days":
-if you have this subject 2 times per week it not placed on two consecutive days. So not Mon/Tue, but Mon/Wed or Mon/Thu.
-if the class has this subject 3 times per week it is not placed on 3 consecutive days. So not Mon/Tue/Wed abut Mon/Tue/Thu or Mon/Wed/Fri.
-if the class has this subject 4 or more times per week, this setting has no effect it is the same as Ideal setting. So it will not put these subjects on the same days