Period Rulesstr
There are 2 kinds of Rules that can be applied to the periods in general
Multi-Period classes - Some classes may require more than one period continuously at the same time
Preferred periods - Some classes may be preferred on specific days and periods
Multi Periodsstr
Multi-Period Rule allows to set the contiguous number of classes to be held for a particular Subject. For example, “Sports” class is 3 periods long. The following video shows how to set this Multi-Period Rule for Sports Class. The Frequency specifies how many times a week the Multi-Period class occurs per week.

Fig. 28 Mutli Period Rulestr
If all Grades will have the same option, you can use Ctrl+Click (Cmd+Click on Mac) to select multiple Grades and edit them to set Multi-Period Rules for all of them at the same time.
Preferred Periodsstr
The Preferred Period Rule provides the ability to specify if certain class should happen on particular days and times. Central High School prefers Sports to occur before lunch. The following video shows how to specify that for the Sports periods from Grades 6-10. Since all Sports classes will have the same preference, we will use Ctrl+Click (Cmd+Click on Mac) to select all the Sports Periods and add the Preferred Period Rule.

Fig. 29 Preferred Period Rulestr
Note
As you Preferred Period rule, keep in mind that you may run into unsatisfied Period Preference if all Groups are preferred at the same time and you don’t have enough Teachers.