Trouble updating a spreadsheet created with Flow

Hi All,

My basic problem is the following: I have a Creator App and whenever a customer record is created, I want to create a spreadsheet titled with their name/record ID etc, and then update this spreadsheet with a new line any time certain parts of the customer record are changed. These fields of interest are in a subform. This creates a sort of "audit log", which I intend to use in Analytics.

I can create the spreadsheet when the record is created. However, when I move to the next step in the flow, I can only select from my old spreadsheet templates saved in Zoho Sheet. I can't select the variable name or write-in the name of the spreadsheet which I created in the previous step.

Does anyone know why this is happening?

Additionally, the subform fields don't show as options under the Creator field list. Does Zoho support using those fields in forms?