Programming the guitar channel is normally very time consuming.
If you play the pattern at a keyboard you will always have to edit - often as much editing that is faster to step program the whole pattern in the sequencer software directly.
The guitar chords are played at more strings, which physically can not be hit at the very same time tick.
Furthermore the chords can be played "downwards" (= the lowest note is hit first) or "upwards" (= the highest note is hit first). This means that there have to be some ticks between the "Note On" events of the single notes in a chord.
Normally the guitar player will continue his hand movement even though he might not hit the strings every time he passes the strings.
Most often the "downwards" movement starts a bit too early, while the "upwards" movement starts at the beat.
Hitting all the strings in a chord will often make the sound to "heavy". Therefore not all strings are hit in all passages.
The strings which are not hit will continue to vibrate (and produce sound) from the preceding time they were hit.
On the other hand the strings which ARE hit must in MIDI terms have a "Note Off" before they are hit again to prevent colliding/overlapping note events.
The chord itself can be played in numerous ways - some easy and some complicated.
When programming an "authentic" chord, notice that the strings are tuned E1, A1, D2, G2, B2 and E3.
In rock music the Power Chord (the root and the fifth) are often used, sometimes doubling the root, e.g. C1, G1 and C2.
If you have more than one guitar channel, it is recommended not to play the chords at the exact same tick, but to move one of the guitars some ticks (app. 15 ticks in 480 ticks per quarter note resolution, more in faster rhythms).
Otherwise the rhythm will sound "mechanical". The longer between the notes the "softer" the rhythm will be.
The guitar can also be used as a melody instrument, e.g. in Intro and Ending style parts.
When playing as a melody instrument, bending the guitar strings is an often used effect. However the programmer must be careful not to bend too fast, which will sound wrong.
Another useable effect is Modulation. But once again, be careful: Too little is better than too much.
As using the effects above produces many MIDI events, it is recommended to strip out some of these to avoid too much MIDI traffic.
When playing a solo melody, another voice than the default voice (defined in the initial setup measure of the style file) is sometimes required. As the keyboard reads voice changes (MIDI Program Change) inside style parts, you just program this change.