And this is analogous to the following scenario. So let's suppose we have a construction worker and the construction worker has to build a building. Now the construction worker cannot build that building without having the blueprint that was created by the architect. And in the same exact analogous way, the template DNA strand is that architect that provides the blueprint, the instructions to actually build the structure that polynucleotide chain. So DNA polymerase obtains its instructions from the preexisting DNA template that is found in that double helical structure. So remember, in that double helix we have two of these template strands that basically run in an anti parallel direction.