Here are the basic rules for uno online:

1. Objective: The goal of Uno is to be the first player to get rid of all the cards in your hand.
2. Deck Setup: Uno Online uses a standard deck of 108 cards. The deck consists of four colors (red, blue, green, and yellow), numbered cards from 0 to 9, and special action cards (Skip, Reverse, Draw Two, and Wild).
3. Starting the Game: The game begins with each player being dealt 7 cards. The top card of the draw pile is placed face-up to start the discard pile.
4. Playing Cards: On your turn, you must play a card from your hand that matches the color, number, or symbol of the card on the top of the discard pile. For example, if the top card is a blue 5, you can play a blue card or a card with the number 5 from your hand.
5. Special Action Cards:

• Skip: When you play a Skip card, the next player in turn is "skipped," and their turn is forfeited.
• Reverse: When you play a Reverse card, the direction of play is reversed. For example, if play was going clockwise, it will switch to counterclockwise.
• Draw Two: When you play a Draw Two card, the next player must draw two cards from the draw pile and skip their turn.
• Wild: When you play a Wild card, you can choose the color that continues the game. The next player must play a card of the chosen color.

6. Challenging Plays: In some versions of Uno, if you suspect that a player has illegally played a card (such as not matching the color when they have a matching card), you can challenge them. If the challenge is successful, the player who made the illegal play must draw extra cards. If the challenge fails, the challenger must draw extra cards.

7. Going Out: When you have one card left in your hand, you must announce "Uno" to let other players know. If you fail to do so and are caught by another player, you must draw two cards as a penalty

8. Winning the Game: The first player to play all their cards successfully wins the game. Points are awarded to the other players based on the cards remaining in their hands. The game usually continues for multiple rounds, and the player with the highest score at the end is declared the overall winner.

Please note that specific rules and variations may vary depending on the version of Uno Online you are playing. It's always a good idea to familiarize yourself with the specific rules of the game before playing.