For each of the Bo2 sets, you pick one of three score options: 2-0 means player 1 wins, 1-1 is a tie, 0-2 means player 2 wins. The players are always in the same order as on the Liquipedia page.
Picking a team for the Ace Match means that in case there is one, you're choosing the player from that team, no matter who that may be. You only get points for correct predictions of players' wins, not for particular team winning or correct team vs team score.
More info: https://tl.net/blogs/545985-prediction-game-ctc-2019-week-1