To open the next restaurant, you need to complete all the quests in your current restaurant.

1. Go to the quest window in the bottom left corner of the restaurant's main screen.
2. If you have enough hats, choose an element of the interior that you want to upgrade.
3. Fill up the restaurant's progress bar to the end.

Once you have completed all quests, a letter window will pop up with a request for help from the owner of the next restaurant.
If the letter from the owner doesn't appear, then you have probably completed all currently available restaurants. We are already working on new restaurants and will add them in an update to the game very soon. Please look out for updates in the App Store or Play Market, or sign up for our social media.
If new restaurants don't appear after you update the game, then contact our support team, and we will try to check your problem as soon as possible.