Work with power query table in Excel

Thanks for taking time to read this.

I have a table created with power query that combines monthly bank statements from different csv files. I want to add a couple of columns to note if it has been matched to who made the transaction and an additional note. Does not work however, since whenever the query gets updates the columns and their values stay but unrelated to the orriginal row.

english is my second languaje so probably I'm not searching in the right place, so I'd appreciate if you can point me on the right direction.

Regards

Solved!

Thank you NormS, it would never ocurred to me to search for "Self Referencing Tables", but is exactly what I was looking for.