When you download the video from conferzoom.org you will receive three files one of these files is the transcription.
Click Record/Upload media
Click Select video, and locate the video (I recommend adding the .mp4 file)
Save your work. Now you should see a video on the page. Click it to play, this will enlarge the video player. Hover you mouse over the "CC" button located on the bottom right of the media player. Click Upload subtitles.
Click on Choose File, located the .vtt file you downloaded. Then click upload.
This is how to upload a video from zoom and including the captions.