In this window the format of the Household Accounting Book table (Table Headers) can be matched to the headers of the import file (File Headers)...select which file header should go with which table header by choosing from the drop down cells. If you want to ignore a certain column of the import file...simply select <Nothing>.

When you are finished matching columns, click the OK button to complete the import. The items of the import file will be added to the existing table.