say means to speak
tell means to give information or facts to someone
So. say doent need an object, but tell needs an object.
he said i won a prize.
he said that he won a prize.
he told me he won a prize.
he said nothing.
he said goodbye.
he told( us )the truth.
the clock tells( us) the time.
you shouldn't tell lies.
i hope this helps.
he told his friends that he had a bad dream last night.