If you drew a single card from the discard pile you are not permitted to discard that card. The Rummy 500 rules for melding are outlined below. Melded cards are scored for the player who melded them, so, if you wish to add your card to someone else’s meld place it in front of yourself.
Players may also ‘lay off’ their cards on pre-existing melds, whether it is their own or other players. You can take cards from within the discard pile if (not on top of it): the card is immediately melded (see below) and you take all the cards above the card you choose to meld. Players may also draw just the top card or more cards from the discard pile.
Players may draw only the top card from the stock pile, keeping it secret from other players, and adding it to your hand.The play begins with the first player to the left of the dealer and moves clockwise.