When creating a duel in game master mode, the players are ordered unintuitively: the player to the left of the screen is Player B, and the player on the right is player A. See this clip, where the streamer is confused because they are trying to create a certain scenario where the player to the left (PlsBeAustralia) starts with more points.

In the case where this is somehow intended behavior, it should be indicated on the game master screen which player is Player A (because it's clearly confusing).