Customize the Add form in the reference table

[EugeneB]

I am using slice to display the Related Reference table, may i know how to do i customer the Add link (highlight in the red at the screenshot below) to display designed form?

Current, when click on the Add button, it is open a generic form, and we want to customize the form display. when checked on the editor it said the view is form? but when click on it. it doesn’t show the form.