This article will help you on how to add a shift to an employee who is not scheduled on both iOS and Android devices. Make sure you are on the mobile version 4.99.0 or higher.
Navigate to the Roster tab and select the day you need to add the shift. To add a shift to an employee who is not already scheduled, select the '+' sign next to the filter icon on iOS or select the '+' sign on the bottom right corner for Android. Then select the employee you are trying to add to the schedule. Remember you will be only able to add shifts to schedules that are posted.
Enter shift information (in-time, out-time, schedule, job, location) and select Save on iOS or the check mark on Android to keep your changes.