The form will accept a CSV file that has SKU numbers on the first column, and quantity on the second column.

The plugin parses the entire CSV, but only looks at the first 2 columns. Everything else will be ignored. The plugin will check if the first item in a row is a valid SKU and if not, ignore that row. The example above is a valid example, as the header row would be ignored (because the first element in the row is not a valid SKU)