When you are in animal restaurant "Restaurant" section, you can swipe down to go to buffet section. You will unlock it when you reach 1500 stars with 300k cod. In this guide, you will know a few ways to get more plates (the green round thing).
Buffet section is important to increase your passive cod income. When you are offline, your buffet income will continue to accumulate, just like the tips.
When you unlock it, you will receive 50 or 100 plates (green round thing), it's a plate to put sushi. You can get your first buffet recipe with that.
You have to quickly unlock this facility to get more plates, so you can unlock more buffet recipe. This is the list of buffet recipe you can purchase with the plates.
Some facility will increase the plates that you can earn per day. Quickly unlock those facility so you can get more plates to unlock more buffet recipe.
My current recipe gives me +5600/hour. So if I go offline for 10 hours, I can get 56k cod
Second way to get more plates is to hire Temp Worker Yolky. Every 4 hours, you can get 55 plates... (this is my current level). If you give raise (increase Yolky pay), it will earn more plates every 4 hours.
One last way is through the task. Complete the task that gives the plate, then you can get it. It always appear in the daily task, so remember to do them all.