These are memory techniques. He creates a combination of techniques such as those of Pietro da Ravenna, Giulio Camillo, Ramon Llull, etc., to create his own art. In other words, with a large number of images, the system becomes fluid if you can use them at high speed.
It converts 24 rooms into 576 locations, as it creates categorical places in alphabetical order. For example, it takes the word “airport” and places an aeroplane in the centre of the room, and in the corners he places objects from that category, such as the pilot’s cap or suit, and so on, three in each corner, or more. He also creates other places with six categorical objects for each room, of which there are 30.
He uses Llull’s techniques to organise images and places, as well as Llull’s own system, which is based on questions and answers, but he does the latter with metaphorical images that represent the concept. In others, he uses other techniques, as anything can serve as an association for him.
He also uses some systems specifically for memorising words, i.e. letter by letter, but his systems encourage you to use them creatively; it is not necessary to use them for something you do not need at the moment.
Something that is not mentioned is that Bruno extracts the techniques from Pietro’s words, so when you use the system, you only have to memorise the acronyms. It is like the saying, “it’s on the tip of my tongue, but I can’t remember it”.
I recommend just extracting ideas from his book. Creating memory palaces is simple nowadays. You can create massive ones if you want; it is no longer necessary to travel anywhere.