Placing your finger on the A note on your keyboard chart, raise(to the right) it to an A#. You should be touching the "accidental" in-between the A and the B note's on your keyboard chart.

When a note is made "flat" it is "lowered" one half step. To "flat" the note "A" we must first locate the note "A" on the keyboard chart.

Placing your finger on the A note on your keyboard chart, lower(to the left) it to an Ab. You should be touching the "accidental" in-between the G and the A note's on your keyboard chart.

If all the key's are a half-step apart, whether black or white, and to sharp or flat a note it is either raised or lowered a half-step, to sharp the E note what has to be done?

According to what has been written, the note must be raised a half-step. If the E is raised a half-step, (to the right), then the "F" is also an E#". Using the "middle C" as the next target flat the C!

If the "C" is lowered a half-step, the "B" neatly take's the place of the Cb.

These natural's with no accidental's in-between them perform "triple" duty. They are Natural notes and can be a Sharp note or can be a Flatted note depending on what key they are being played in.