There are a number of functions available to change the roster.  There are a few different ways to access these functions.

Some Examples

• The roster toolbar at the top of the roster screen.
  
• Using shortcuts on your keyboard. For example, to copy a shift select a shift, CTRL C, move to an empty cell where you want the shift to be copied, CTRL V to paste the shift.
• Using the list available by right clicking on a shift with your mouse while in the roster section of the roster screen