The header content of the column is used as the value of the corresponding attribute of TOP. All columns in a table are stored as attributes of TOP. When the program enters a footprint, it runs a query on the db table. All columns (fields) of the table will be stored as attributes in the part. So, to add a particular attribute to the footprint, you shall just add a column to the table of the database and populate the value. Columns whose name begins with "underscore" (_) are not stored as TOP attributes. Be careful not to change the name of the standard fields. For example, the "_MATERIALE" attribute inserted into the sheet will not be saved as attribute of the part. These attributes can be used for internal calculations to the worksheet without affecting the values of the attributes of the parts.