I think you gotta first get a camera and sell enough photos to the guy in the midnight and then he'll give you the pendent
Gym? Do you mean training? Just go to Boruto's room and there should be a fist icon on top of the ? Icon. Click it and do training to increase strength stat and to unlock uchiha
You gotta reach a certain strength level and you'll get the encounter. Keep training at mornings till you get it.
