In order to use a clean CentOS VM Virtualbox with the default image, the following steps are needed:

Use the DVD edition of Centos 7 and boot it with your virtualization manager of choice

During install create a user and a root password when prompted

After install is complete, log in as root and give the user administrator rights:

sudo usermod -aG wheel [myusername]

Now switch to the user account

sudo su [myusername]

Next ensure that networking is enabled, typically this is done by editing the following file. The exact name will depend on your virtualization manager.

sudo vi /etc/sysconfig/network-scripts/ifcfg-enp0s3

Now press a to edit and edit the bottom line so that it says

ONBOOT=yes

Now press escape and type

:wq

Then press enter

Now reboot the machine with

sudo reboot

The machine is now ready to install Zegami, you may want to install wget in order to download Zegami, this is done with:

sudo yum install -y wget