You have ended your turn and the world market is now open. You now receive offers from nations selling the types of commodities that you tried to buy on the trade screen.
After each offer is acted upon by you (the potential buyer) any commodities remaining unpurchased are passed on to other nations that bid on those commodities.
Of course you might not be the first buyer in line. The offers you see may already have been passed up by other nations acting ahead of you.
