To create a completely new data-type, so that in future this new data-type can be attached to plans, you actually need to use the Jet ‘profile manager’ tool, not the plan-manager tool.
Likewise, to delete an existing data-type, you need to use the profile-manager tool. The use of the profile-manager tool is discussed in the Jet ‘Profile Management’ manual.
You cannot define an entirely new kind of service data using the product manager tool discussed in the manual you are reading now, you can only ‘attach’ one of the existing kinds of service data to an existing plan. To learn how to define a new kind of service data, please consult the Jet ‘Profile Manager’ manual.