However if you want to see a Flow in the "My Flow" library, you have to Export it.
NOTE - Once exported, your Flow will be also immediately available in your Dropbox folder. For more information read here
To export a Flow, just tap on the arrow icon on top of it's editing panel, which is visible when the Flow side-panel is open (tap the blue flow icon to open it).
Load a Flow
If you have saved a Flow then it will be immediately available in your "My Flows" library.
To Load it inside a new Set just go in Edit mode, tap Load, then tap the "My Flows" panel in the top of the panel, this will open the list of your saved Flows.