if a hero has 12 health and has already taken 11 damage from a previous round; in the new round the hero takes on additional 4 damage, do u discard the 3 remaining damage or would they apply to the hero's wounded side?

as soon as they are wounded filp card to the wounded side, remove strain as well. (not sure if you discard harmful conditions and focus) some assistance to this answer would help

When a hero is defeated for the first time:

1. You flip over the character card to the wounded side.

2. All damage tokens are discarded (the excess damage was inflicted already). So they have no damage tokens.

3. Discard only excess strain to the new endurance attribute (usually one less than when healthy).

4. Keep all attributes (good (focus) and bad (bleeds and stuns).

But he doesn't flip at the end of the attack he flips once he has damage equal to his HP thus flipping him while still in the combat?

It's confusing me because it doesn't say they flip to wounded at the end of the attack they were damaged in.

But he doesn't flip at the end of the attack he flips once he has damage equal to his HP thus flipping him while still in the combat?

It doesn't matter if he's still "in the combat" or not -- what matters is that damage is applied all at once, not one-by-one. So with 11/12 damage he is not yet wounded, and then suffers 4 damage all at once, going straight to 15/12. He is now wounded, so he flips and discards all damage tokens, going back to 0/12 on the wounded side.