openSIS allows the user to schedule a single student into multiple course periods at once. To schedule a student into more than one course periods go to Scheduling >> Student Schedule and search the student you want to schedule.
Click on the student's name.
Now click on the Add a Course option, a new window with all Subjects, Course & course periods will open up. Select as many course periods as per requirement (course periods can be under one or more than one courses) by clicking on the check boxes marked in red. Then click on Add followed by Confirm. Now the selected course periods would be assigned to the student's schedule.
In this way a student can be scheduled into multiple course period in one go.