How to allow a user to be able to view/edit/manage timesheets for other users:
1. Go to Administration > Resources, and search for the user for which you want to allow rights to manage their team's timesheets, and select that user
2. go to Resource's Access Rights and add "Timesheets - Navigate" global access right to this user
2. under the Resource's Access Rights dropdown, select "instance rights", then click on "Resource - Enter Time"
3. here, click "add" and then select the users you want to allow this user to be able to manage timesheets for, and click "add" again - this will return you back to the list of users for which this user now has access to manage timesheets for