Follow the steps to cast Vimeo through Chromecast:

1- Setup: Ensure your Chromecast-enabled device and your iOS device are connected to the same Wi-Fi network.

2- Open the Vimeo app: Open the Vimeo app and find the Video you want to watch.

3- Screen Mirroring: Use the app screen mirroring feature to mirror your device’s screen to your Chromecast-enabled TV. 

4- Choose Chromecast: Select your Chromecast-enabled device from the list of available devices.

5- Start Mirroring: Your device’s screen should now be mirrored on your TV with Vimeo Content.