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Movies & TV is the default player in Windows 10. You can use Windows Media Center if you wish but if you simply double click the file you wish to play it will play in the Movies & TV app by default. This player only accepts .srt files for subtitles however and the file we get from Discovery Education Streaming is a .smi file. In order to play it we're going to have to convert the file. We can use a tool such as this online converter to do so. Just follow that link to the converter, upload the file with the subtitle and select SMI -> SRT and Do not convert for the second option as shown below. You do not need to enter anything for Sync adjustment unless your subtitles are out of sync with the video for some reason. Then hit Conversion to download. This will download your file.
When you have the video open in the Video player click on the icon for closed captioning (the speech bubble in the bottom left corner) and click Choose subtitle file.
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