Click your name in the top right, then click Settings
On the settings menu click TIMESHEETS, then click Timesheet groups
Choose a Timesheets group you would like to enable the clocking in for and click on the edit icon ✏️.
Select Allow employees under this group to clock in from a mobile device
Once done, as long as an employee is in that timesheet group a clock in widget should appear on the dashboard of your employee's mobile device.