Some basic facts

1) There are 7 main notes which are denoted as C, D, E, F, G, A, B, C.
2) In between these notes are a few sharp notes which are denoted by # (sharp symbol).
3) So the complete series becomes C, C#, D, D#, E, F, F# G, G#, A, A#, B, C
4) You might be wondering why there is no E# and B# present. This is because these notes do not exist.
5) The difference between two notes is represented by a semitone for example the difference between C and C# is a semitone, similarly the difference between C# and D is represented by a semitone.
6) The difference between two alternate notes is represented by a tone.For example the difference between C and D is called a tone, similarly the difference between C# and D# is also a tone.

This is the guitar fret-board showing all the notes including sharps.

1) We already know that the set of notes are C, C#, D, D#, E, F, F# G, G#, A, A#, B, C.
2) The note C#(c sharp) can also be represented by Bb (B flat).Similarly D# can be written as Eb (E flat) and G# can be written as Ab (A flat). The chart below explains it.

This is the guitar fretboard showing all the notes including flats.

Note that the first note on the 1st string is E. From the series of notes we know that the pattern coming after E would be F, F#, G, G#, A, A#, B, C and so on which is also clear from the notes on the string of 1st string.

Similarly first note on the 2nd string is B, hence C, C#, D, D#, E, F, F# G, G#, A, A# and so on which is also clear from the notes on the string of 2nd string.

The first note on the 3rd string is G, hence G#, A, A#, B, C, C#, D, D#, E, F, F# and so on which is also clear from the notes on the string of 3rd string.

Likewise, the first note on the 4th string is D, hence D#, E, F, F# G, G#, A, A#, B, C, C# and so on which is also clear from the notes on the string of 4th string.

And the first note on the 5th string is A, hence A#, B, C, C#, D, D#, E, F, F# and so on which is also clear from the notes on the string of 5th string.

Similarly first note on the 6th string is E, hence F, F# G, G#, A, A#, B, C, C#, D, D#, E and so on which is also clear from the notes on the string of 6th string.