Schools often have double and sometimes triple periods built into the timetable, especially at GCSE level and above.
If you need to separate linked periods so teachers can take the register in a double or triple lesson, you need to go to the administration settings and click on the Registers tab.
After clicking on the Registers tab, scroll down to the Separate linked periods field and turn this ON.
This will separate all linked double and triple lessons in the register, allowing for separate registration for each lesson.
Lastly, scroll to the bottom of the tab and click Save to save your settings.