How do I add a custom button to map fields

How do I add a custom button to map fields

In my CRM we have created a custom module 'Delegates', I want the ability to convert a contact to a delegate and it pull across some of the relevant information such as Company, Title, Name, Email, Phone Number.

I have inputted the Deluge code I thought would work but it doesn't seem to work. This resource seems to be a similar scenario:  https://www.zoho.com/crm/resources/tips/functions-po-from-so.html

Any Help would be appreciated"