Need to add a new sort order

Hi, I need to add a new sort order to G2. I've already created a new column in ItemAttributesMap that is basically a clone of orderWeight and written the code to manipulate it, but I can't figure out how to sort by it. I see adding sort orders mentioned a couple times in the forums, once with the statement that it's fairly easy, but no mention of how to do it - any help would be greatly appreciated!

Thanks