To make this template the polymerase must open the DNA double helix exposing the nucleotide code as partially unraveled single strands. I don't know how the polymerase keeps track of which strand of DNA to copy. This makes for a total DNA alphabet of 64 letters. For the purpose of this article it is only necessary to know that a certain subset of these 64 possible trinucleotide sequences are coded to the various amino acids that make up proteins. Proteins are wadded-up strands made from beads of amino acid.
Carbohydrates are variable length strands made from beads of sugar.
This obsessive involvement with beads and the consequent underlying nature of all biological life being built from beads surely must point to something profound and subtle. Why heck darn, one could even look at organs and other cellular masses as three-dimensional beaded tapestries where each cell composes a single bead. However, we have already wandered far afield from our original topic. As I recall we left the main thread of thought shortly after wondering how Type II RNA polymerase keeps track of which strand of DNA to copy. We may as well leave that question in the same bucket as the mysteries of how polymerase knows when and which gene to copy.