I want to start with new save data.

You can start a new save data by doing the following:

1. Please click on the gear icon in the title screen or the ≡ icon on the upper right corner of the in-game screen to enter the options screen.
2. Select "Other".
3. Select an empry save data slot in the "Load save date" section.

Please note that if all three slots are already in use, you will first need to delete an unwanted save data in "Delete saved data" in step 2 before proceeding to step 3.