Fuikein tea suck as bonsai outside their native climate, and especially for a newbie. They're touchy to being moved, over/under watered, need lots of light to be happy, and are prone to many pests and diseases. If you're relegated to growing bonsai inside, check into a green island ficus. They're far more tolerant.
For this one, identify the pests and research the best treatment to eradicate them, then go do it.
Use this tree to learn how to water properly.
When you do kill it, keep the pot, and move on to the next tree. Best to have several trees so you're not worrying one to death.