Write some Software

I have 1,2,3 or more csv files with and ID and quantity. This information needs to be enriched with information out of the woocommerce database. The ID will match one product and from this product more information is needed in the output csv file. The input csv files 1,2,3, n can have the same ID with different quantities. The target csv file does only have one row with this ID and adds the input csv files with file name and quantity in columns, the more input files the more columns of course. All ID's out of one input file have to show in the same column. The name for the columns will be taken out of the target file which has a unique identifier and will add 001, 002, 003 for each input file added. I tried to visualize it...