Go to the Employee's profile

Go to their 'Work' tab

Click into 'Schedule field' 

Select the Schedules you want to add them to 

Press 'Save'

Go to the "Schedule'

You can view the schedules in the location by selecting the drop-down box next to the blue 'Actions' button

You will be able to see any shifts scheduled in other locations or schedules for employees, these will appear as white box

Shifts will appear coloured if they are for the schedule/location you are currently viewing