....This is the key signature of G Major/E Minor. Can you see that there is a # sign on the
top line (F) of the stave? This means that every time any F is written in the music an F#
should be played instead.
Key signatures with flats consist of a series of bs on the lines/spaces of the notes which
should be flattened. So, in this example....
....there are 2 b signs on the middle line (B) and the top space (E). This means that every
time any B or E is written it should be played Bb and Eb respectively.
Key signatures are found in Bass Clef as well. Here is G Major/E Minor in the Bass Clef....
And here is Bb Major/G Minor in the Bass Clef....