I used to have one of those. You cannot add to the rhythms/styles held in the keyboard; you can only use/play them from the floppy disk. So if you load a non-standard style file from a floppy disk into your KN930 keyboard and use/play it, it will dissappear from your keyboard over a matter of hours after you switch off. Then when you switch on the keyboard again the following day you will have to reload that style file in order to use it.
In the end you find that you keep all your standard and non-standard settings for the various pieces of music you play, on floppy disk, and reload them when after the other.
Don't forget to use the panel memories on the right hand side of the keyboard to set up your progressive use of each style file's variations and changes of melody line instrument.