There is an icon on the world map to enter. After entering, click the picture on the left. It will show how many music boxes you have. The music boxes dance in a fixed mode, and then the system will add more. To open it, you need to go to the mall. Go buy a key. A copper key costs one yuan, a silver key costs three yuan, and a gold key costs five yuan.

I personally think it is not cost-effective to buy it, because the gift is not permanent. You can Wait and see tomorrow, I will give you a copper key at double time tomorrow.