If Spain sell soccer balls to the united states then Spain:

has an absolute advantage over the U.S. in making soccer balls

can produce more soccer balls that the U.S. given the same resources

has the ability to produce soccer balls at a loser opportunity cost than the united states can.

does not have any trade barriers with the U.S.

If Japan has an absolute advantage over the U.S. in making TV's then Japan:

probably sell TVs to the U.S

produces more TVs than the U.S. using the same resources.

has the ability to produce TVs at a lower opportunity cost than the U.S.

it will have no reason to trade with the U.S.