The user sees other TimeTracker user names because the user is set as Team Lead for a Team and the user type on the TT user screen is set as Team.
If the user wants to track time only for herself please remove her name from "Team Lead" if she is set as Team Lead for an Team. And set the user as individual user, click here to know more about creating an ID for Individual user.
Ask the user to Logout and re-login to the TimeTracker application on the device to see only her name and is able to track time only for herself.