Custom Field to the "Details" Search Module

I have a Search Module that is displaying "Basic Information" and "Details." I need to add a custom field to one of these two groups.

I see how to add the custom field to "Basic Information" in the group manager, but when activating custom fields in the search module a new dropdown menu is created instead of this custom field being added to "Category" and "Price."

Can anyone tell me how to either hardcode or configure OSproperty to allow a custom field (in this case "square feet") to be added to Basic Info with"Category and Price" or Details with "Bedrooms/Floors etc.)

Hi Jason,
I am confuse with your question. When you create new custom fields in OS Property, the custom fields will be saved to the corresponding extra field groups. And from the search module, the custom fields will be shown in the group of them [+].
OS Property has some fixed fields like Square feet, bedrooms, bathrooms, rooms v.v. I think they are basic fields of properties system.
Thanks
Dam