I don't think the average soldier is expected to internalize the entire document. It's more a training tool, or maybe taken into the field as a reference if someone thinks it's relevant. One of my favorite army field manuals is "FM 3-05.213: Special Forces Use of Pack Animal". 99.999% of soldiers don't need to know that when an elephant's body temperature reaches 38.3 degrees celsius you need to let it rest, or the fact that the average working llama needs 4 liters of water per day. But if they ever find themselves utilizing war elephants (which is strongly discouraged in the manual!), they know that somewhere in this 225 page tome they can find information to help them succeed.