Subtitle archives need to be a SRT format coded in UTF-8. They are loaded a as a property of the clips on Timeline, therefore, the .srt files must be generated separately. Uploading subtitles is an available option as a +SRT button placed in the pop up window after hitting the Import button in the Editor's Library.
Your .srt files are now ready, so go to the project editor ─EDITOR─ and import all the .srt files that you are going to use in your Interactive Video. Make sure your subtitle files are generated for singular clips and not fur the full interactive experiencie, because they are processed separately.
In the Timeline, select the video you want to add subtitles to, the Properties panel will show the option “Subtitles”. Click on it and select the language of your subtitles and select the corresponding file. After you have made sure you have selected the right file, click on Add Subtitle to add more languages’ subtitles.
When several languages are used, Default can be used to set a language to start the playback with.