I am not sure if I follow all of your questions, but I hope this helps.
1. Your floppy is probably /dev/fd0 or /dev/fd1
2. For a computer the is not connected to the net and being setup by
a newbie you really should consider spending the $10 and having the cd
available to you. It is much simpler that downloading on another machine and
then transfering to your debian gnu/linux box. Yes you can do this directly
but since your system is not really setup yet there is a slight catch22 here.
Also you are probably going to want to reinstall several times as you learn
more. This is much easier with a cd.
In the meanwhile you might just want to play around with the base system while
you are learning.
