Issue installing Debian

[Zack]

Hi, guys, how's it going? I got one question:
I installed the system using the CD 1. Everything was fine (the
installation process). But, when the system runs, it shows the command
line mode only, not the graphical environment, I mean, not GNOME. What
should I do to resolve this issue? As I wrote above, all the installation
process was ok. Thanks.