Despite being sold as indoor and beginner trees they are far from that. 99% of the Carmonas dies in the hands of beginners. It is a terribly difficult plant to keep in a temperate climate, besides from,placing it inside which is even worse.
First of all, there is no such thing as an indoor tree, not one tree in the entire world lives naturally indoors. There are of course (sub)tropical plants that can’t survive in colder climates but they too have to be placed outdoors in summer, only to be stored in a cool frostfree, not heated bright room, so not in our living rooms that are too dry, lack light and ventilation.
So don’t be disappointed when your Carmona dies ( pretty sure it will), but if you are interested in bonsai, this is a good place to start.