How to add more attributes in the Mass Change Excel sheet?

Summary:

How to add additional attributes in the Excel file to execute Mass Change on attributes while using Guided Tasks?

Content (please ensure you mask any confidential information):

This is the first time we're using Product Management's Guided Tasks to perform Mass Updates on Item Attribute. We reached to this point where we can see the Excel file, however we would need to see more attributes in it and be able to add attributes as Master Data Management needs.

How to do it?

Any help is welcome.

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

26A