Here's a general method for installing IPTV apps on a Hisense Smart TV if the Duplecast app is available on the platform:
Power on your Hisense Smart TV and ensure it's connected to the internet.
Navigate to the "Apps" or "Smart Apps" section on your TV's home screen.
Open the app store or app gallery on your Hisense TV. It might be called "VIDAA" or "Opera TV."
Use the search function within the app store to search for "Duplecast."
If you find the Duplecast app in the app store, select it, and then choose to install or download it.
Follow any on-screen prompts to complete the installation.
Once installed, you should be able to open and use the Duplecast app. You may need to log in with your Duplecast account if required.
Please note that app availability can vary by region and TV model, so if the Duplecast app is not available in the app store, you may need to explore other options for streaming IPTV content on your Hisense Smart TV.
I recommend checking the official Duplecast website or contacting their customer support for the most up-to-date information on app availability and installation methods for your specific TV model.