buyer cap confused download ebook general link meaning particular product products sales sell selling times total validity

I'm selling an eBook for the first time and am confused by the "download link validity" thing.

Is it for each particular buyer or for the product in general? Meaning...it's set at "3" right now.

Does this mean that one buyer can download the product three times or that I will only sell three products in total?

That's per buyer. There is no cap on sales.