Hierarchy of Actions drill
The hierarchy of actions drill should be practiced when you have done all its components in set drills before. At first, forget about proper feet positions in guard, beautiful lunges, etc., and just focus on the pattern of the blade actions. The most common attack in rapier is by disengage after a stringering. There are four common defences against it: parry riposte in two tempi; parry riposte in one tempo, or counterattack with opposition; a counterattack with avoidance; and a counter-disengage.
Then we add the counters. When stringered, your partner should disengage with a feint to draw one of the above responses from you. Be co-operative; the goal of this drill is not to teach convincing feints, but to illustrate the fundamental structure of the system. Against a parry-riposte in two tempi: feint and disengage, avoiding the parry. Against a counterattack: feint and parry-riposte in two tempi. Against an avoidance: feint, and parry riposte in one tempo, or if you can, counterattack. Against the attack by counterdisengage you can do any of the four things that you can do against an attack by disengage; but in this drill, redisengage.
You may notice that during this drill, the plays of the plates occur: from the stringering in quarta, steps 3 and 4 are the plays of plate 7; step 5 can be done as in plate 11 or 14 (feel free to look them up!). You will also find step 7 on plate 15. From the stringering in seconda, step 1 can be done as the scannatura (plate 13); steps 3 and 4 look a lot like plate 16; steps 5 and 6 can be done as in plate 17 or 19; and so on. Once you can identify what type of action any instruction in The Book is, working out the plays from the plate is much, much easier.