The setup used by the author requires six pedals, arranged in two sets of three. The pedals are daisy-chained into the keyboard connector, and duplicate the actions of selected keys. One set provides the modifiers <Control>, <Shift> and <Alt>, and the other provides three types of action, referred to here as <Other>, <Move>, and <Select>.
If using the common commercially available pedals in which each unit has a large central pedal and a smaller pedal along each side, the recommended setup puts <Shift> and <Move> onto the large pedals.
<Move> is the main action, moving forward in the current dimension, and corresponds to the <Right> cursor key. S-Move moves in the other direction in the same dimension.
<Other> and S-Other provide the <DOWN> and <UP> actions of Versor.
<Select> brings up a menu, using the Text Mode Menus (see Menu Bar (emacs)), and you can then move along the menu using <Move> and S-Move, and select an entry using <Select>, which will either bring up a further menu, or run the selected command.
Some of these commands read their arguments through a system built on top of completing-read, that is designed to allow fast selection of possibilities without needing typing. See Flexi-choose, for details of this.