In music notation, sharps and flats are placed in front of the notes they affect; e.g., F sharp is written on the staff thus: -
The sharp or flat sign must be placed on the same line or space as the note. Here is the full range of notes in the first position, including all sharps and flats.
For the relative positions of these notes on the fretboard, refer back to the fretboard diagram from the previous lesson. The notes marked in brackets are called enharmonic notes because they have the same pitch, but different names; e.g., A# and Bb have the same position on the fretboard, but different positions on the staff.