Im new to kittycats, just got 2 kitties, well 3 but the one we bought from a store and she didnt tell us you cant open the box so we lost that kitty.

So i did some research and went to the main store and bought 2 more. Im concerned how they sleep. It appears their energy is low. We have beds and a cat tree for them and have set their bed for their home. Is there something I need to do. 1 day old and 2 day old. Also is there a way to salvage the kitty we lost due to opening the box? I really wish she would have told us how to open the kitty and birth it smh a real shame, not so much cause of the money we paid but because she was really cute and we wanted her. Thank you for your help!