New Seller and petrified!

ASINs are Amazon Standard Identification Numbers. As the name implies, they only work on the Amazon website and are allocated automatically, as random letter/number combinations to products that don’t have a barcode that is generally recognised outside Amazon - EANs etc

If your suppliers are using barcodes that are not registered, that is a bit worrying, as that seems to imply they have made them up, or bought them from dubious sources

You should only add your stock to those listings if it is EXACTLY the same - full description, brand name and especially EAN (European Article Number - 13 digit barcode like those on Heinz baked beans or most other products you can buy on the high street)

If you buy a pack of 100 blue widgets with any kind of product code, and then split it up to sell as packs of 10, you either have to get a new product code (EAN etc) from GS1 for your pack of 10 or apply for GTIN exemption, because the original product code is for a pack of 100 and you are misleading buyers if you list a pack of 10 under that code

Not sure what you mean by this. You can only list products on Amazon as “New” if you buy them direct from the manufacturer, the manufacturer’s authorised distributor or a wholesaler acceptable to Amazon (cash and carry outlets are not acceptable). If you buy from any other source, you can only list as “Used - Like New” at best and in some categories (such as food), you cannot list as “Used” at all. Clothes also cannot be listed as “Used”

If you create bundles by combining products, you again need to obtain an EAN for the bundle or apply for GTIN exemption. You should also check with the manufacturers of each item that they are happy for you to sell their goods on Amazon as part of a bundle