You can earn stars by completing your customer orders.

To complete an order, you should create the requested items by merging. You can always check the related item chain by tapping on the item in the order.

The orders will have a green checkmark on them once you prepare every requested item. Tap on the checkmark button to complete your order and earn stars. If you want to see all your current orders, you can always scroll left and check them.

There is another indicator both on the order itself and the board for the order status. If you see a green base behind the order, it means you already have one of the items requested somewhere on your board. If you see a tiny green checkmark on the bottom-left corner of the item, it means that this item is requested by one of your orders.