If you have iOS device and you want to use DISH Anywhere then hare are the ways that you have to follow to access on your Roku Device:
First you have to go to apple app store and download Web video cast
With the help of Web video cast you will get Dish anywhere
Go to DishAnywhere URL and start casting with your Roku device
But it must to connect same both device with the same network
For more visit: https://thewebbings.com/dish-anywhere-on-roku/