What command do I need to use to get the GUI?
Im on Debian KDE. I tried startx to no avail.
Thanks in advance.

You could tryIf you log in at the console you can also look at to see if that shows up any problems.

In Debian, by default, the sudoers file is not configured; sudo will not work unless you choose to configure it use the visudo command. You would need to use su; see man su for more. (As far as I know, only the *buntus and their derivatives rely on sudo out of the box.)

Also, by default, Debian boots to a GUI Display Manager. What did you do so as not to install a display manager? (I'm not criticizing, I'm just curious.)

If you are booting to the command line, you need to configure an .xinitrc file to start a GUI. Here's a HOWTO from the Debian wiki: https://wiki.debian.org/Xinitrc

Alternatively, you could install a display manager. https://wiki.debian.org/DisplayManager

check your .xinitrc file if you're going to be using startx to start x .
you need to tell it what to start.

did you install xorg and all of the necessary items ?