The definition of intonation in this context means: "accuracy of pitch in playing a stringed instrument such as a guitar".
If you notice that notes higher up on the neck sound out of tune (typically above the 12th fret) while the guitar is in tune when playing open notes, then you will need to make an adjustment of the saddle holding the string at the bridge of the guitar to correct the intonation and increase the accuracy of pitch across the fretboard.
Also, note that if you change the gauge of strings it may be required to adjust the intonation to ensure accurate pitch across the fretboard.
- Allen Key (included)
1. Check pitch of open note & at 12th fret
First, using a tuner check to make sure that the guitar is in tune.
Then using a soft to medium pick attack play the lowest open note (or harmonic note at the 12th fret) then compare the pitch to the pitch fretted at the 12th fret; If it is more than a few cents off then an adjustment is warranted.
2. Adjust the string saddle accordingly
In order to adjust the string, you will need to loosen the string until you can move it out of the way in order to access the screw that holds the saddle in place on the bridge.
Then loosen the screw that holds the saddle to the bridge using the allen key provided in the gig-bag.
Now time to make the adjustment!
If the fretted note is sharp: Adjust the saddle towards the bridge.
If the fretted note is flat: Adjust the saddle towards the "headstock" of the guitar.
Once the saddle has been adjusted, tighten the saddle to the bridge using the allen key, then re-tune the string & check the pitch of the open note against the 12th fret pitch and repeat this process as needed until you are within a few cents.
3. Repeat for each string
Repeat this process for each string as needed.