You need to use FNSKU label to cover original barcode of your item, so Amazon receiving staff can scan it to add your item into their warehouse.
Amazon FBA UPS Shiping Label
After you put your items into the shipping boxes, weigh them and pay the inbound shipment, you can print out UPS shipping label.
TurboLister will convert Amazon shipping labels into the 4×6 labels, so you can print them out with your thermal printer. TurboLister supports any thermal printer that can print out a 4×6 label, such as Dymo 4XL and Zebra 2844 to print out 4 × 6 UPS shipping label.