want to add people to payroll, membership problem?

I want to add another person to the payroll, I see in this help site that I go to my account and click on people to do this, however I do not have an option called "people", perhaps I do not have the right type of membership.
Can you please give me details of how I can get the right membership? Or tell me if there is a problem with my account?
My current membership is "Monthly UK Limited Company plan". Which I would have thought would cover multiple employees.