how to customize the seeded cmk xsl file to add additional fields

Summary:

Requirement is to pass the details of Sales Agreement number, line numbers, but we do not see any fileds to hold this information.
How to identify the fields to hold the Sales Agreement number for Sales order in PO Inbound file

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

xsl:stylesheet version="1.0"

Code Snippet (add any code snippets that support your topic, if applicable):