Your roles are the many hats you wear in your life. If you are using Week Plan in a team, then the roles represent the different roles in the team.
Some of the common roles: Son/Daughter, Husband/Wife, Friend, Colleague, Entrepreneur, etc..
One role we like to add is "Self" to represent the things you could do for your health, personal growth, etc...
Don't overdo it. A healthy number of roles would be under 7. If you manage two different projects, they might still be under the same role "Entrepreneur" or "Work".
Thinking about your tasks in term of Roles is strong concept of Week Plan to help you keep a balanced life.