Employees go to HR Tools > HR > Available Shifts (also reachable from the Dashboard's Pick up a shift card or the email link). The table "Open shifts you can pick up" lists open requests that match one of their job roles or are marked Any Role, with Role, Date, Time, Notes. Clicking I'm Available records the signup; the button then changes to Withdraw, which removes it. Employees need the Sign Up for Shift Requests permission and must be linked to an employee record ("Employee profile not found.").