The logic for playing is based on the classic UNO set rules, so you should be familiar already if you've played standard UNO before. There are a few minor alterations listed below, along with some standard-but-pedantic rules that you might want to brush up on.

• If a player reaches "UNO" (one card in hand) but does not "yell UNO" within 3 seconds, they must draw another 2 cards.
• This version of UNO does not use a points system, but continues until a player runs out of cards.
• The game may start with a Wild or Wild Draw 4 card, which means the beginning player may play any card of their choosing.
• The beginning player is a random selection from all players.
• Turns are taken in the order that each player joined before/after the randomly selected beginning player. This order may be reversed with a reverse card, and a player may be skipped with a skip card.
• It is not illegal to play a Draw 4 card even if the player has other cards that may be played.

Here are a few ways to start this game:

• With a slash command: /uno players:... cards:...
• In challenge mode with /challenge or by right clicking a user and pressing "Challenge" under "Apps"