We also use CentOS 7 on the real machines. This makes life easier, because we only need to know CentOS config style. Of cause you could use other Linux distribution on the real host.
1. Step: Install CentOS 7
2. Step: Install KVM
Required packages:
yum install qemu-kvm libvirt bridge-utils
Start libvirt:
systemctl start libvirtd systemctl enable libvirtd
Install KVM real machine
This is a excellent article on how to setup the real host system: https://www.linuxtechi.com/install-kvm-hypervisor-on-centos-7-and-rhel-7/