First check the delivery types and item categories that are contained in the standard SAP R/3 System.
You have to keep in mind that they cannot be seen in isolation but are closely linked to sales document types and billing types. Therefore also take into account the actions that are listed for sales documents and billing documents.
The definition is only complete if you have also edited the menu options for the functions. You could, for example, define separate scheduling for your own delivery type. In this case, you would have to edit the menu options "Delivery types" and "Scheduling" in relation to one another.
Check to what extent you can use the defaults that are contained in the standard SAP R/3 System and to what extent you have to make changes to represent your business processes.
For additional information on the functions of delivery types see the manual "SD Shipping", chapter "Delivery Types".