can’t install swappable cdrom drive

Hi I am Eric.I own a gateway 200 120mhz 3pc laptop.Which has a swappable cdrom+ floppy . I can not get the cdrom installed.because the bios config setup has no information on cdrom.there is:- boot to h/drive and boot to floppy.There is no ,boot to cdrom.And I can not get it to change And I need to install win 98 .. some one told me to edit the config line in .Edit .com I dont know about these things yet. and I love this little laptop I will like to keep.I need someone to walk me through the steps step by step.Please help me.Eric