Access m.youtube.com on your smartphone or tablet, go to the page of the video you want to play, and tap the Trancy floating button on the right side of the video page to enable it.

Select a word or sentence with your finger and tap the translation icon in the sidebar to initiate word translation

Tap the screen three times in succession with two fingers or tap the Trancy icon on the side of the screen to enable full-text comparative translation or full-text replacement translation.

Tap the sentences and paragraphs you want to translate twice in succession with two fingers to enable sentence or paragraph translation.