Column Expression Syntax issue

Hi Team,

New to Knime, Trying to use Column Expression node to set the barcode based on UOM

If UOM =“PCS” barcode code to start with “100000”+ Product Code (6 Digits), and then workout a checksum digit to make the barcode 13 digits long

If UOM =“PACK” barcode code to start with “200000”+ Product Code (6 Digits), and then workout a checksum digit to make the barcode 13 digits long

If UOM =“CARTON” barcode code to start with “300000”+ Product Code (6 Digits), and then workout a checksum digit to make the barcode 13 digits long

What is the best way to script it in Column expression node.

Appreciate your help. Thanks