A ticket represents $0.01 in bet value (1 Ticket = $0.01 of the skin you submitted EX: $5.00 Skin = 500 Tickets). The more tickets a player has, the more chances of winning he gets. As soon as a round is over, the winning ticket number will be calculated based on the random percentage and the total number of tickets with the following formula:
Math.floor((TotalNumberOfTickets - 0.0000000001) * (winnerPercentage / 100))
Keep in mind that the order of the tickets are the same as the order of the deposit. For instance, if the first player places $50 into the pot, he will own tickets 1-5000, then if the second player places $20, he will own tickets from 5001 to 7001. This will keep going until the pot is full at which point the round is set to end. Also note that the bots may accept a few late bets if there is any.
Dotajackpots trade bots will never add you or ask you for skins.