How to Reveal the ProgramData/Flow Folders
C:\ProgramData is a hidden folder by default. There are a few ways to work around this. You can always access it by pasting the path directly into Windows Explorer. You can follow the steps below to reveal all hidden folders (note - this is an all or nothing feature. After activating it you will see ALL previously hidden folders). If that clutter bothers you, consider simply creating a shortcut to C:\ProgramData\Flow instead of revealing hidden folders.
Navigate to the Control Panel and find Folder Options
Click Show hidden files, folders, and drives
Open a folder and navigate through your C: drive to the Program Data folder
This is where all the Flow information is archived and where you will save your Backgrounds, Layouts, etc.