Learn one chord at a time. The diagram shows where to put your fingers; play the chord and the trainer listens. It advances to the next chord once you hold the right one cleanly.
Blue-outlined letters are the notes this chord needs. They turn green as the mic hears them; an orange letter is a note you're playing that isn't in the chord (a muted string ringing, usually). Get all the chord's notes sounding together and hold for a moment. With auto-advance on, play it cleanly twice (release and re-strum between) to move to the next chord.