Dueling Club is a regularly held, time-limited, special event in which you can participate to try to gain special rewards, such as notebooks, to exchange for rare items in them game, such as pets.
You'll find the dueling club in the Dungeons level at the end of the hall. Look for the Dueling Club icon, and just tab it to enter.
Dueling Club
It's worth heading into the event to take a look even if you don't feel you can complete enough duels to win the top prizes and there are some prizes to win along the way, you even get something for just visiting the dueling club!
Quest Complete - Thanks for the free Gem
However after the first visit, you may get stuck in actually starting the duel! So... Just leave the room, then enter it again and tap the crossed wands icon above the chalkboard.
To play a match you nee tickets, you start off with 3 and use per duel.
PvP or Bots?
While the game may give the impression this is a PvP event, it does seems that the actual characters that you face, while being actual wizards of other players are controlled by the game. If you are a higher level thatn your opponent, then it's likely you will know stronger spells and should have a better chance of winning as possibly you will need to make fewer wins in each duel.
How to get more dueling tickets?
Once you have used all three of your tickets, the game will restore your tickets after 4 hours and you can then duel some more. The countdown only starts when you are out of tickets. Alternatively you can spend gems to get 4 more tickets. The price may vary, but currently I see it as 55 gems for 3 tickets.
More Dueling Tickets Please