Hi,
First you need to find what is the base table for your field(Shade code2) which is going to enhance.
Shade code 2 is alread loaded thru any DSO/cube or master data loads?
Take source team help and find the table.
later you can add field to your data source extract and unhide it at RSA6.
later implement logic at CMOD, take abap expert help to write the cmod logic.
Thanks