When the triggered ability resolves, first the player whose turn it is (if it isn't your turn) chooses which creature they will sacrifice, then each other player in turn order does the same, then all chosen creatures are sacrificed at the same time
If you want still more out of your 3 mana investment, Uro, Titan of Natures Wrath lets you draw a card, gain 3 life, put a land onto the battlefield, and then do it again later in the game for 4 mana and 5 other cards in your graveyard via the Escape mechanic
Theres a lot heading our way this year, so take a look at whats available
Starting with Theros: Beyond Death in January 2020, Wizards started putting cards from these Commander sets in the main set's Collector or Set boosters
Gogo, Mysterious Mime* Gogo clone just wish you were more interesting than a middling clone that is undersized when not copying things on attack, even if you can copy legendary creatures 118