Newbie Question Race/Class Discard

[TheKGBjr]

I have searched the forums and just need a bit of clarification.
We played our first game today and for some reason my son must have drawn 3 race cards. He can't just put those cards on the table because they are not "items" (ones with values) but if he already chose a race can he simply put the extra races in the discard pile or does he have to discard the race he currently is, play the new one and discard it?
I must be missing something because he had several race/class cards on the table but it didn't seem right.
I promise I searched the forum for an answer and found several topics, read the FAQ and the rules :) but my old brain just seems to not be getting it.
We had a blast anyway!