a week is still early for a new hamster, so it’s probably still getting used to a new environment. so, it’s normal to hide for a bit. as for taming, make sure to wash your hands with unscented soap and don’t use any scented lotions and hand soaps before training. another thing you should do is rub your hands in the substrate. this will help stop the nipping. also, make sure you’re using treats and positive reinforcement
also, the size of the wheel could be a problem. if the wheel is too small, they will not use it