Heres what I would do:
extract the kernel source into /usr/src/linux-2.4.0test10
to a make menuconfig in that directory, once you have configure it do a make dep, make bzImage, make modules, make modules_install. Copy bzImage from /usr/src/linux-2.4.-test10/arch/i386/boot/ to /boot/ and rename it vmlinuz-2.4.0test10
Open lilo.conf in /etc and add:
append=what ever paramters are appended on other kernels
root=same as other kernel
save the file and run lilo. reboot, type linuxTest at the prompt and it will load the new kernel. Beware..the lilo stuff shouldn't be done if you aren't using lilo as a boot loader.