If the swipes are not available in the biometric database, you need to get in touch with your Biometric vendor to fix the issue.
Once the swipe details are available on the Employee Swipe page ( Path : Leave >> Admin Section) on greytHR,you need to manually Process the Attendance for your employees.
Kindly note, the automatic attendance process setup on greytHR will take care of the attendance process only for the previous day; for the backdated attendance process you need to manually process the attendance by following the manual method.
Step 1 : Navigate to the Process Attendance tab from the Leave >> Admin Section.
Step 2 : Select the Dates
Step 3 : Click on the Process.