my problem is this master list is a running excel sheet so ill be appending my list with new items coming every time I run the workflow with new source file. If I want to add lets say more chairs and vases, what node shall I use so that the item code that will be automatically generated is subsequent to the existing ones
You can make use of Rank node to get unique id per item by specifying grouping column inside it and Ordinal as Mode. After that Rule Engine node can be used to add prefix (CH, TB…) depending on item and finish it off with String Manipulation node to create desired code using join() function for joining and padLeft() for 4 digit part of it.