Download and decompress the fancylogin tarball.
Enter the fancylogin-XYZ directory, where XYZ is the fancylogin version.
Edit the files login/config.h and environment.h after your preferences (for experts only!).
Do a 'make'.
Do a 'make install'. This installs fancylogin into the /sbin directory. You should be root while doing this.
Do a 'make sampleconf'. This copies a sample theme to the directory /etc.
Edit your /etc/inittab file. You will find a line like '1:2345:respawn:/sbin/mingetty tty1' somewhere in this file. Please replace the 'mingetty' by 'mingetty.fancylogin' to make the system start fancylogin after booting. It always save to leave the standard login program on one console, if anything of the installation failed or so.
Do a 'telinit Q', and press Ctrl-C (if you're not logged in) or Ctrl-D (if you're logged in) to start fancylogin.