Send Whatsapp message from Whatsapp template with custom variables

Hi,

I'm trying to do some basic integration for sending WhatsApp messages from Zoho CRM using Zoho Desk whatsapp templates.

When creating new whatsapp template in Zoho Desk we can choose ticket related fields as variables but it's not clear how to use this variables via API.

For example:

A whatsapp template on Zoho Desk is: Hey ${Contacts.First Name} ...

And i want to fill the "first name" variable with value via API.

Thanks