These instructions are for users with extensive user rights, such as admins in Silverbucket

Editing someone else's actual hours can be done by finding the person through the search field in the Timesheet by clicking 'Show person selection'.

This button displays a dropdown list from which you can search the desired person. Clicking the person's name forwards you to their timesheet page, in which you can edit their hours.

Navigating back to your own timesheet page is done by removing the selected person by clicking her name, or by searching yourself from the list and clicking it.