Hope you realise that I didn't actually create Sienna, so I'm not entirely sure why you came to me :/
Anyway, there are six squares in the Gym - You can see them as they will stand out from the regular floor tiles. Keep clicking on them and you'll eventually have the two tickets. You will have a one-in-ten change of finding the ticket each time you interact with the ground, so don't give up if you don't get one after a couple of tries :)