For approving your employees' period transactions you need to go to Time reporting --> Period transactions --> List or Grid view.
Both views offer the "Approve All" button, which allows you to approve all transactions marked as "Open" within the selected time frame.
On the right side of each employee's row, the status of their registered transactions is displayed, allowing for individual approvals. In Grid view, approving a single row will approve all transactions associated with that particular employee.
Clicking on a status will display the transaction history, detailing when it was added and who approved it.
Already approved transactions can be re-opened and the open ones can be deleted as well.