Essentially, all you have to do is copy your KickStart config file to /ks.cfg on the RedHat boot floppy, e.g.
mcopy ks.cfg a:
However - the RedHat boot floppy is pretty full, and you may find that you have to delete some of the other files to make room for the KickStart config file. I was able to make enough room for mine by deleting the various message files normally displayed by the SYSLINUX boot loader, e.g.
mdel a:\*.msg
Another approach would be to throw away the drivers for some of the hardware you don't have - see the section on modifying the boot floppy below.
You may also want to edit syslinux.cfg, the SYSLINUX config file. This also lives in the top level directory of the RedHat boot floppy. For instance, the following syslinux.cfg will cause KickStart mode to be entered into automatically as the machine boots up, without the normal delay:
default ks prompt 0 label ks kernel vmlinuz append ks=floppy initrd=initrd.img
Note that you almost probably want to base your boot and supplementary floppies on the most recent disk images available in the updates/i386 on your local RedHat mirror site. Older images may be buggy or have driver support for less hardware.