How can I enter time on behalf of someone else?
If you have been authorized as a designated alternate timesheet user for another person, then you can create timesheets via +Timesheet as you would normally. Select for whom you would like to create the timesheet on the right side of the screen. Similarly, if you are editing another person's existing timesheet, you can do this in Time > List, then choose the person on the right side of the screen.
If you are an Admin and if you have configured Unanet to allow Admin edits (not advised for DCAA compliance typically), then you can edit timesheets via People > List > Clock Icon.