- You input a sentence in Japanese (easier on mobile where you can handwrite kanji you don't know) - App translates the sentence, explains the grammar, and gives you a list of flash cards - You choose some flash cards to save for studying later - You input a question about the explanation for more information - App explains some more and gives you more flash cards - Repeat
And then you can review the flash cards later with the built-in SRS system.
There's a video to explain the UI on the front page.