That advice may be useful, but don't do it now. If the trunk is healthy, not oozing, rotting or frothing, then just wait - eventually (you may have to wait till end of June) new growth should appear either up the trunk or from the base, or both. When it does, cut back to that. If the trunk is damaged, and particularly if its oozing orangey gunk, then just keep an eye on it for the time being - cutting back beyond that point is probably necessary, but this is best left till April if you want to give the remains of the plant every chance to regrow. This assumes your palm tree is a Cordyline australis.

The idea in cutting at an angle is to keep water from collecting on the cut, and encouraging rot. The candle wax is also to keep fungi out, but expert opinions are divided on that step. Some maintain that it just seals disease organisms in, and interferes with the formation of melanin, tannins, and other fungus-fighting chemicals the plant naturally produces at the cut. When other forms of Cordyline or Dracaena are shipped as cuttings from farms in Hawaii to wholesale greenhouses, they are waxed on the ends, but that is mainly to prevent water loss.

Agree there are mixed opinions regarding sealing the cut on Cordyline, Tug - I'm inclined to say don't put anything on it.