Paste the full link into the top input on Home and click Start. If no subtitles are found, you will be prompted to try another video.
We rely on YouTube's own captions first. If none are available you'll see a message and can try another video.
Mark words on the video page; statuses sync to My Library. Practice pulls from new/starred words.
Subtitles and words are cached locally for 1 hour. Account data is stored in backend; deletion flow to be added.