first boot your linux system with your other loader or boot floppy, then set up lilo's config file: /etc/lilo.conf . once that's done just run lilo from the shell: /sbin/lilo -v (-v for v_erbose information). lilo is now installed to the first disk's mbr and will be available after your next reboot.
if you need help with the config check the lilo man page, if you still need help then post back here...
hope this helps!