If the Use Virtual Clock option is enabled, the users won't be able to add timesheets manually.
Who has added the Timesheets?
Click Access Button
then click HR Admin.
Click Queries then click the plus + icon.
From the left-hand area, select Break Timesheet.
From the right-hand selection area, tick:
Timesheet Date.
Timesheet Added By.
Click Next twice, then name the query, and click Next once again.
Who has Virtual Clock turned on?
Click Access Button
Click Queries then click the plus + icon.
From the left-hand area, select Employee Details.
From the right-hand selection area, tick Use Virtual Clock.
Click Next, then click on Use Virtual Clock, and select Equals: On.
Click Next, name the query then click Next once again.