First, load the video into the program. After that, click on "Subtitle" button to open the Edit Audio/Subtitle window. Go to "Subtitle" panel and click plus button to add your subtitle file. You can set language, position, font color and size of your subtitle. Then you can click on "Audio Track" button to enter the Edit Audi Track window. Click on the "+" to add your audio track list. You can add up to 8 audio tracks into the video.