Fretboard with notes
The fretboard is the top part of the neck on a guitar, between the body and the headstock. On the diagram below you can learn all the notes on the guitar fretboard - after the 12th fret it's all repeating again (i.e. the 13th fret is the same as the 1st, only one octave higher).
It's important for your development as a guitar player to learn the position of every note. This helps the understanding of chord theory and makes it easier to play melodies, solos and licks.
It starts with the open strings, when continues with the notes on fret 1 to 12.
The fretboard on the guitar illustrated. After the 12th fret it's all repeating again.
In the fretboard diagram, C# (C sharp) is used and not Db (D flat), and so on. If you for example are looking for the note Ab (A flat) this is the same as G# (G sharp).
In the middle of some frets you can find dots. One dot can be found on the third, the fifth, the seventh, the ninth, the fifteen and the seventeenth frets; two dots can be found on the twelfth fret. These have no specific meaning besides making it easier to find the right fret fast.
On the guitar fretboard the same note is represented many times, seven to eight times to be precise. Some of the notes are in different octaves. For example, the C note is represented seven times on the first twelve frets. If we start counting from the left on the lowest string the first two C notes are in one octave, the next three are in a second octave and the last two in a third octave.
If you find it very difficult to learn all the notes on the fretboard, you should at least start by learning the tones on the low E and the A strings because the roots of chords are often on these strings. As you can observe, the lowest and the highest strings are identical.
Fretboard note decals
If you still are uncertain there is ways to get around. For example, you could tape some notes on the side of the guitar neck. If you want it to be a little fancier you could get special made note decals
as in the picture below.