How do you modulate from E flat major to G flat major?

E flat, A flat, and B flat are used.

Simply, because the E is flattened!

None. If you are playing in G Major there is only one sharpe ( F) no flats. But if you play in E Minor there is one flat ( E ). G Major ( notes/tones) : G, A , B , C , D , E , Fsharpe , GE Minor (...

G Flat Major is a key signature: it goes as such: b=flat, #=sharp, and *=natural Gb, Ab, Bb, Cb, Db, Eb, F*, G

The tonic of E flat major is E flat. Its dominant is B flat and its subdominant is A flat.