fret: 1 2 3 4 5 6 7 8 9 10 11 12 e|F-----G-----A-----B--C-----D-----E---- B|C-----D-----E--F-----G-----A-----B---- G|---A-----B--C-----D-----E--F-----G---- D|---E--F-----G-----A-----B--C-----D---- A|---B--C-----D-----E--F-----G-----A---- E|F-----G-----A-----B--C-----D-----E---- 1 2 3 4 5 6 7 8 9 10 11 12These are the notes on the first 12 frets on the guitar. I didn't list the rest because all the notes start over at the 12th fret. That's called an 'octave.' You might have noticed there are gaps on this chart. to fill in the gaps, either take the note above it and put a 'b' next to it (flat), or the note below it and put a '#' next to it (sharp).
Example:
2nd fret on the E string is either (both) an F# or a Gb.
8th fret on the D string is either (both) an A# or a Bb.