The creation of subtitles for videos on YouTube is very easy.
Proceed as follows:
– upload your video on YouTube,
– in the list of your “Uploaded videos”, select the one you want to manage and click on Edit,
– in the settings check for the tab “Subtitles”
– download the automatic transcription of the voice (it is actually automatic for English voices only, but the file itself can help anyway with the time schedule of the voice),
– prepare the translation, create a Caption file on the basis of the transcription and upload it,
– your video is now ready to be in two or more languages!
More details on YouTube Help site.