Create custom field in admin product-section

I am trying to build an addon for creating a custom field in admin product page, for showing “custom shipping text” for a particular product, as client wishes.



“Shipping Properties” doesn't allow any text to be entered, only values.



I've checked the addon creation document at “docs.cs-cart.com” but still confused, as to where to put my custom addon template file for adding the field in admin product section ?



Also how to set field to be bulk value addable & editable in admin ?



Can somebody help me with this ?



My cs-cart version is 4.0.1 multivendor, I guess addon documentation for v4 is still not available in advanced section.



Thanks in advance



Vivek