@TatteredBella like any other listing, you can list any quantity. It defaults to one, so yes, when it sells you need to relist if you have more.
If you have quantities as part of the Variation - a red hat, a blue hat, and a green hat, for example - you need to check the box "quantities vary" when you create or update the Variation.
Now your Options you enter will have a default quantity of one each, which you can change, if needed.
This way, when the red hat sells, it will show as "sold out" in the drop- down, and will relist with the other options still available.
