Thanks for posting in the Roku Community!
We understand that you inquiring about how to cast StarPlus on your Roku device.
Please be aware that to use casting on Roku, the supported app must be installed on both your mobile device and your Roku streaming device. You'll want to contact StarPlus directly to inquire further if their channel app supports the casting feature.
For Android devices, you may watch the channel on your Roku by sharing the content from your mobile device. Here’s how: How to screen mirror your Android™ or Windows® phone to your Roku® streaming device | Official Roku ...
If you have any other questions or concerns, please let us know.