You have a server, but want to setup VNC to access the GUI? We use this tutorial for our systems and wanted to share. (ALT is an IT consulting company, offering technical support for Mac, PC and Linux systems). We try to keep things updated, but tutorials have a tendency of exiring, so some steps may be different for newer versions. We've used Ubuntu 16.04 to install, but it should work with others as well.
Install the components
apt-get -y install ubuntu-desktop tightvncserver xfce4 xfce4-goodies autocutsel
Add the vnc user and give it a password:
adduser vnc
passwd vnc
You can add vnc as sudo, so you could run apps as root. Edit the sudoers file:
echo "vnc ALL=(ALL) ALL" >> /etc/sudoers