This page covers the fundamentals of how to stand with a sword in your hand and contains some ideas about moving and shaping up to an opponent.
Both Paternoster and Cavalcabo are explicit in their description of the fencer's stance. It is rear-weighted with the feet in-line such that the heel of the front foot is directly in front of the ankle of the rear foot. The sword is held in the hand with the elbow bent; the arm is not extended as Agrippa recommends. De Heredia calls out that the hand is held a palm width and a half above the belt with the point low. The left hand is held forward up near the face as a last ditch defense against attacks.
Both Cavalcabo and Paternoster use for four Agrippan guard positions although they classify them differently. Note that each guard position is defined by the position of the arm, not the orientation of the blade.
Both writers agree that tierce and quarte are the best general purpose guards for attack and defense: tierce for attacking, quarte for defending. Cavalcabo classifies the four guards into two categories: premiere, seconde and tierce in one category and quarte in its own. Paternoster, however, classes premiere and seconde into one category and tierce and quarte into the other.
The guard positions mean little by themselves. Their usefulness comes in using them as a means of gaining a tactical advantage over an opponent. This is the concept of the counter-guard. For Cavalcabo:
Cavalcabo and Paternoster disagree violently in their classification and descriptions of the footwork they recommend. There may be a way to synthesise these notions but that is a topic for another day.
Paternoster presents four classifications which essentially form two actions used in a variety of situations. In short, in close measure only, he recommends expanding the stance by moving the front foot first then bringing the rear foot forward to maintain a proper stance. In all measures, one can bring the rear foot towards the front foot (either half way or right up to it) then expand forward with the front foot to return to a proper stance.
Cavalcabo speaks about footwork very differently and much more in line with Agrippa's ideas. For him, footwork serves to move the body either forwards, backwards or to either side of the opponent.
This will be made plain in the exercises.