Tap on the yellow shopping cart icon at the bottom of the screen to find the lunch boxes! You can open some of them to win permanent boosters for your restaurants! Don't worry if you change your venue: you will keep all the cards previously unlocked 😉

 

Remember to tap on the card button (lower-right corner icon) when you see a small notification over it. That means you have enough cards to level up a specific booster!) 

 

Please consider that you can win more than one card for the same booster. The more cards you get for the same upgrade, the higher you can level them up.