Knowing the notes on the guitar fretboard is what turns shapes into music. Once you can name the note under your finger, chord charts, scales and tunes start to make sense, and you stop relying on tab alone.
What Note? keeps it small on purpose: the six open strings (E A D G B E) and the first three frets — the part of the neck every beginner plays first. A marker lands on a string and fret; tap the note on the keyboard. Press Hear it to train your ear at the same time.
Start with Naturals (no sharps or flats), move to Chromatic when you're quick, or pick Scale to practise just the notes of one key, such as G, D or C major, the keys most beginner songs use. A few minutes a day and the notes become automatic.