Colum

This is a bit more complicated.
You have broadly two groups of bidders. One who bid by specifying the yield they expect. And another that wants to buy a certain $ amt. (competitive vs noncompetitive).
The ‘noncompetitive’ bidders will be able to get the bills/notes etc. at the price decided (best yield) from among the competitive bidders. There are restrictions as to how much you can buy as a noncompetitive bidders, since they will always be a “winner” in the auction (like 5Million$).
Keep in mind, this is not how normal auctions work.