Copying Columns between Sheets or Setting up Vlookup Value Column for Datamesh


I am trying to setting up a data flow from one document to another. We are working with two documents, one is the central one with numerous number of columns. From this document I would like to copy information to our second document, which has different column. Of course, some are matching and for those we would like the data to flow automatically. 

Workflow Automation is not suitable as it copies all columns when copying a row.

We also have a Datamesh, however there you have to have Vlookup Value column, which is as I understand a preexisting matching column to drive data, and this we do not have. Second document and its data is based on the data of the first one.

I have checked previous community discusions on this topic, and found out that you can use formulas, either VLOOKUP or INDEX/MATCh, but my formula skills are quite poor and I remain with unsolved problem. I see this as potentially helping us set up the "tracking ID" column that would serve as Vlookup Value for Datamesh Config.

Could you please advise me how I can get information form one file and its selected columns to another file's corresponding columns (whitout copying all columns)?

Or how to create identical columns in two sheets the simplest possible way with column formula?

Thank you for your help!