If you want to start the game afresh, you can reinstall it.
First check if the game had been linked to Facebook / Apple sign in / Game Center previously (Go to Settings -> My Accounts):
◼️ If the game had not been connected and saved before, you can just reinstall it and start a new adventure.
◼️ If the game was saved in the past, you need to tap on Facebook / Apple sign in / Game Center button and select "Local" option in a new window.
This will start your game from level 1.
But remember that in this case we will lose all the information about your account, and we will not be able to restore it.