How to Get the values from the Array?

Summary

How to Get the values from the Array?

Content

Hi,

I have created a process for supplier creation in ERP CLOUD. Here I have created a webform for entering supplier details and also I have created a webservice for this process to create a supplier in erp cloud. I need to map the values of the form(Data available in left side refers to form data ) with the data in the REST service. Here Supplier contacts(under service Task) is an array. I'm trying to map the values as

createSupplier.supplierRow.supplierContacts[3].firstName. If I try to run the process,it get suspended and the below error occurred.