How to create Task in Zoho CRM using workflows custom function?

How to create Task in Zoho CRM using workflows custom function?

Hi,

I want to create Tasks (records in Task module) from custom functions in Workflows. 
Here I am getting an issue to map values in Related-To field that will contain the name/lookup of the module to which this task is related.

How can I map the related module in that field?

Please help.

Thanks in advance....