Add A Free-Text Record Box from NetSuite

KGPayables Expensify Customer Posts: 7 Expensify Newcomer

We have a custom column in NetSuite to be able to track the serial numbers of our different assets. It's a free-text column. I've tried adding it in Expensify as Custom Segment/Record, but receive an error message that the Custom Record refers to a custom list (which isn't the case). How can I add this column to Expensify to be able to add the serial number and have it populate in NS?