Settle a question...

Let's say I'm dealing blackjack (at a charity event). All player cards are face up.

Player has two 8's and wants to split. (Could be another card, I just chose 8's.)

Does a card get dealt to each 8, then the first hand is played, then the second?

Or does a card get dealt only to the first 8, that hand is played to completion, then a card dealt to the second 8 and that hand is played?

I watched a few Youtube videos and have seen it done both ways. It's been a while since I was at a casino and don't recall.