Working groups are used in a few places - approvals and workflows.
To keep them up-to-date is a manual process - there's no automatic allocation of employee's to groups.
Follow these instructions to add a member to an existing working group:
- Go to Settings > Settings & Configuration > Core HR > Org Structure > Working Groups (Edit)
- Click on the Payroll working group on the left to open the "Working Group" page
- In the "Group Members" field, click on the 'book' on the right
- In the "Picker" form use the "Search" field to find the user
- Double-click to select the user and then click "OK"
- Now back on the "Working Group" page, click "Add members to Group"
- Screenshot below for reference