Whenever the work-flow provides a verification, review, approval, etc., must be defined the perpetrators.
The 
button (that you can find in “configure category”) opens a window for selecting a work-flow-time:
Select from the section not enabled (left) the name of the person you intend to enable verification or approval of the document and press the button 
: the name will be moved to the section Entitled (right). May be chosen even more names simultaneously, while pressing <ctrl>.
If you want to remove the qualification to a person, do the reverse procedure: select from the section Entitled and, by pressing the button 
, move it to the section not enabled .
In the field request Deadline, today’s date is proposed, but you can change it for, in the message to the user involved, is a date by which its intervention is required on the document object.