Remove and add new field to calculator

How to remove post code field from the product page cal and add a new field as district here as shown in the picture. https://drive.google.com/file/d/1CgMjMIVrb4avhqn4-skCJfgN8IDpJFiY/view?usp=sharing

https://www.ads-software.com/support/topic/important-change-the-position-of-the-cal/ – this what im using to show the cal in the product page.

Have lots of hopes in your support. Hope to hear from you soon.
Thank you