5th fret, 2nd string = E
4th fret, 3rd string = B
5th fret, 4th string = G
5th fret, 5th string = D
5th fret, 6th string = A
To check the 1st string, play the 2nd string at the 5th fret.
This will sound an "E". Adjust the 1st string open to this exact pitch.
Continue as the diagram on the left indicates.
WARNING: DO NOT OVER TIGHTEN THE STRINGS.