You can duplicate flows; for example, if you want to experiment with some ideas without affecting the original flow, or if you want to copy material with any barlines you have added.
Procedure
In Setup mode, in the Flows panel, right-click the flow you want to duplicate and choose Duplicate Flow from the context menu.
Result
A new flow is added, containing all the music and players of the original flow. It is automatically added to all full score and part layouts.