Everyone can hum Jingle Bells. Roughly nobody can play it on guitar in a way that sounds like more than one very lonely note poking at a fretboard. That is the gap this clip climbs into: the melody you already know, plus the chords underneath it, all coming out of a single guitar at the same time — no band, no piano, no small child on a triangle.
This is a MelodyChords arrangement, which is the polite term for "chord melody": the tune lives on the top strings while the harmony hangs off the notes below. It is also, and I promise this is the truth, my last Christmas song of the year. Consider it a festive parting gift before I go back to riffs that scare the neighbours.
An arrangement like this works because Jingle Bells is harmonically almost embarrassingly friendly: it is built on the three pillars of Western music — the I, IV and V chords in one major key. The whole trick is to put the melody note on top of whichever of those chords is fair game underneath, and to keep that melody note as the highest, loudest thing your fingers pluck.
Concrete takeaway: don't try to voice every full chord. Grab the melody note first, then add only the two or three chord tones you can physically reach without your hand cramping into a claw. On the long held "sleigh" and "way" notes you have all the time in the world to fill in the harmony; on the fast "jingle-jingle-jingle" bits, just let the melody carry it and drop the chords. Your ear fills in the rest — it already knows the song better than you do. If you want more of this, the same logic powers Last Christmas and basically every solo arrangement I record.
And that's it — no more sleigh bells from me until they legally have to come back. If this bought you a warm holiday minute and you'd like the Guitar Pro files and tabs, you can throw a snowball my way on Patreon.