A sign language-interpreted video actually consists of two videos that the viewer can switch between. Start by uploading both versions to Streamio as usual. Here you can read more about how to upload video to Streamio. Then go to the library and select the non-sign language-interpreted version. Press the Accessibility button and select the sign interpreted version from the drop-down list.
Now when we are watching the video, the symbol of sign language interpretation has appeared in the upper right corner. If we click on it, we will instead see the sign language-interpreted version of the film.