Keep them outside, out of direct sun. I keep mine in an unheated greenhouse in the winter.
Water them well. It's a bit late to be re-potting them now. If you do then a mixture of 50% sharp sand 50% compost will do or you can spend a fortune on Bonsai Potting compost. You'll need to prune the roots back a bit if you do. These tend to come potted in a real clayey soil so if you're not re-potting then keep them well watered. It'll appreciate a regular spray with a water mister. It'll need fertiliser too, loads of stuff out there. I don't bother with fancy bonsai ones, they're just overpriced, I use maxicrop, just dilute it and water it on once a week, just water in mid summer though