To begin with from what youre saying you allready have Lilo Installed.
If you want to see the list of O/S's installed to choose from them press the left Shift button when you see the LiLo.xx.xx prompt appear.
If not the n in order to install Lilo to your MBR you need to go to the command Line and run LiloConfig (Ithink its upercase L cant remember)
You should now be presented with the Lilobuilder screens.
The process itself is relatively simple just go thru the options starting from 1 read the instructions and add bootable partitions etc.....
Eventually you will be prompted to state where to Install Lilo simply select MasteBootRecord (MBR) from the list and you should be fine.
Note ----- Keep the bootdisk in case something goes wrong (It shouldnt but you can never be too Carefull)
If you cant run liloconfig go to google or www.ltdp.org
and search for lilo
Hope this helps!!!
If you need more info go to http://gus-br.linuxmag.com.br/livro/on-line/c1710.html