Please note: only users with the "Manage Business" permission can manage roles.
If your account has roles setup, users with the view only permission will only see task lists which their roles are assigned to. Roles are a great way to filter out the visual noise of other lists so users can focus on what's only pertinent to them.
This feature is not applicable to users with the "Edit Task Lists" permission, as these users will see all task lists regardless of roles assigned.
First, setup your roles on your account:
Now that your roles are setup, click here to see how to assign roles to task lists.