Create a schedule template that has both NOT FILLED shifts and Assigned Shifts to Employees on it. You can either create a new template or edit an existing template to add employees.
Please note that you can assign multiple employees for the same shift, and if that employee is available ShiftNote will schedule them for that template shift. If they are not available to work, because of time off, or they are already scheduled somewhere else ShiftNote will leave that shift NOT FILLED.
To create a mixed template leave the Automatically Use Employees When Available box blank in the template editor as shown in the Auto Assigned box below.