If you want to restart a fresh game you can create a new profile...
1) Open the in game options page you will see at the bottom "Explore Save Game Folder". Clicking that will open you save folder.
2) Next I would recommend going up one folder and renaming "Save" to "OldSave" or something.
3) Now when you replay you will start at the beginning again - but if you ever need to return to your original save games you can rename the Save folders again.