In The Debian Way, you create a deb file which contains information about where the kernel is (and makes the kernel and yada-yada). In the "normal" way, you put things where they need to be right away. You need to install your modules and then configure lilo to point to the new kernel and then run lilo. If you are not doing things The Debian Way your "install" will look like this:
cp arch/i386/boot/bzImage /boot/vmlinuz.<date>
vi /etc/lilo.conf and copy the structure of your existing kernel. Do NOT delete the reference to your existing kernel! You need to point lilo to the "vmlinuz" file that was created when you compiled the kernel above
lilo (yup, just exactly like that.) Lilo will let you know if it's going to have major problems loading the new kernel.
Do NOT forget to run lilo before rebooting. Type lilo. It's that easy (and that easy to forget).