Each of the setups will ask you different questions about your systems hardware etc. It’s very important to configure everything as close as possible to your settings. If you don’t, you could have problems getting X to run. Once all that is done, try out X by typing startx. If all goes well you should see some color pattern or perhaps a small toolbar. If something goes wrong don’t worry, you will see a bunch of error messages.
It is probably due to errors made while setting up xf86config. You can try to play with the config file and see if you can make it work, or copy down the error message and come visit us on #LinuxGroup.