Accidentals

Sharps raise a note by one half step.
For example: An "A" with a sharp in front of it becomes an "A-sharp" -the black key just to the right of "A."

A "B" with a sharp in front of it is called a "B-sharp." Since there is not black key to the right of "B," the note "B-sharp" is the same as "C" on the piano.

Flats lower a note by a half step.
For example" An "A" with a flat in front of it becomes an "A-flat" -the black key just to the left of "A."
An "F" with a flat in front of it is called an "F-flat" and, since there is no black key to the left of "F," sounds the same as the note "E," on the piano.

Naturals cancel any accidental that came before.

Double flats lower a note by two half steps.

Double sharps raise a note by two half steps.