install and build qemu on ubuntu 20.04 code example
Example: install qemu ubuntu 20.04
sudo apt install qemu qemu-utils qemu-kvm virt-manager libvirt-daemon-system libvirt-clients bridge-utils
Then you will have to add an user to the following using Uses and Group software
kvm, libvirt, dnsmasq, libvirt-qemu
Installation of Uses and Group software
sudo apt install gnome-system-tools