With placeholder screens in Flows, you can create flows from scratch even if your designs are not ready yet. Then you can easily replace those screens when the designs are exported to Zeplin.
You can click the placeholder icon on the bottom left of your flow canvas to use a placeholder screen:
From the toolbar above the placeholder screen, you can choose the screen orientation, represented with mobile or web icons; and you can select the type of your screen from one of the premade templates:
Once your design is ready and exported to Zeplin, you can update the placeholder with the actual screen by using the “Swap with a screen” button revealed when you click on the placeholder screen: