The current player chooses first, then each other player chooses in turn order. A player does not have to reveal the chosen card, so long as it is clear *which* card was chosen. After all choices are made, the cards are put onto the battlefield simultaneously.
04-10-2004
wotc
If the cards being put onto the battlefield also require choices, those choices are made after all players choose their card. The active player makes choices for their card (if any), then the other players (if any) in turn order.
04-10-2004
wotc
Players choose cards during resolution, not announcement.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.