If you plan to fill in and submit timesheets later, to prevent you from forgetting to do this you can set a reminder for yourself.
On the relevant Timesheet, tap on the alarm icon in the right corner.
If you already have existing reminders, these are listed.
Tap Edit reminder to amend an existing reminder.
Tap Add a new reminder to create a new one.
Choose the time.
Label the reminder.
Select what day(s) to repeat the reminder
When done, tap Save reminder.
Once create a reminder, you amend them at any time.
If you need to remove a reminder, tap Edit reminder, then tap Delete.
If there is a reminder you temporarily don't need to use but don't want to delete, you can also toggle reminders on and off instead.